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<h1 id="firstHeading" class="firstHeading" lang="en"><span dir="auto">Bird migration</span></h1>
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<div id="mw-content-text" lang="en" dir="ltr" class="mw-content-ltr"><div class="dablink">For more information on animal migration in general, see <a href="Animal_migration" webstripperwas="http://en.wikipedia.org/wiki/Animal_migration" title="Animal migration">Animal migration</a>.</div>
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<div class="thumbinner" style="width:302px;"><a href="File3ABrantaLeucopsisMigration.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:BrantaLeucopsisMigration.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/a/a3/BrantaLeucopsisMigration.jpg/300px-BrantaLeucopsisMigration.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/a/a3/BrantaLeucopsisMigration.jpg/300px-BrantaLeucopsisMigration.jpg" width="300" height="137" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/BrantaLeucopsisMigration.jpg/450px-BrantaLeucopsisMigration.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a3/BrantaLeucopsisMigration.jpg/600px-BrantaLeucopsisMigration.jpg 2x" /></a>
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<div class="magnify"><a href="File3ABrantaLeucopsisMigration.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:BrantaLeucopsisMigration.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
A flock of <a href="Barnacle_Goose" webstripperwas="http://en.wikipedia.org/wiki/Barnacle_Goose" title="Barnacle Goose">Barnacle Geese</a> during autumn migration</div>
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<div class="thumbinner" style="width:302px;"><a href="File3AMigrationroutes.svg" webstripperwas="http://en.wikipedia.org/wiki/File:Migrationroutes.svg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/7/75/Migrationroutes.svg/300px-Migrationroutes.svg.png" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Migrationroutes.svg/300px-Migrationroutes.svg.png" width="300" height="282" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/75/Migrationroutes.svg/450px-Migrationroutes.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/75/Migrationroutes.svg/600px-Migrationroutes.svg.png 2x" /></a>
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Examples of long distance bird migration routes.</div>
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<p><b>Bird migration</b> is the regular seasonal movement, often north and south along a <a href="Flyway" webstripperwas="http://en.wikipedia.org/wiki/Flyway" title="Flyway">flyway</a> between breeding and wintering grounds, undertaken by many species of <a href="Bird.html" webstripperwas="/wiki/Bird" title="Bird">birds</a>. Migration, which carries high costs in predation and mortality, including from hunting by humans, is driven primarily by availability of food. Migration occurs mainly in the Northern Hemisphere where birds are funnelled on to specific routes by natural barriers such as the <a href="Mediterranean_Sea" webstripperwas="http://en.wikipedia.org/wiki/Mediterranean_Sea" title="Mediterranean Sea">Mediterranean Sea</a>.</p>
<p>Historically, migration has been recorded as much as 3,000 years ago by <a href="Ancient_Greece" webstripperwas="http://en.wikipedia.org/wiki/Ancient_Greece" title="Ancient Greece">Ancient Greek</a> authors including <a href="Homer" webstripperwas="http://en.wikipedia.org/wiki/Homer" title="Homer">Homer</a> and <a href="Aristotle.html" webstripperwas="/wiki/Aristotle" title="Aristotle">Aristotle</a>, and in the <a href="Book_of_Job" webstripperwas="http://en.wikipedia.org/wiki/Book_of_Job" title="Book of Job">Book of Job</a>, for species such as <a href="Stork" webstripperwas="http://en.wikipedia.org/wiki/Stork" title="Stork">stork</a>, <a href="European_Turtle_Dove" webstripperwas="http://en.wikipedia.org/wiki/European_Turtle_Dove" title="European Turtle Dove" class="mw-redirect">Turtle Doves</a>, and <a href="Swallow" webstripperwas="http://en.wikipedia.org/wiki/Swallow" title="Swallow">swallows</a>. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and scientific studies have used techniques including <a href="Bird_ringing" webstripperwas="http://en.wikipedia.org/wiki/Bird_ringing" title="Bird ringing">bird ringing</a> and satellite tracking. Threats to migratory birds have grown with habitat destruction especially of stopover and wintering sites, as well as structures such as power lines and wind farms.</p>
<p>The <a href="Arctic_Tern" webstripperwas="http://en.wikipedia.org/wiki/Arctic_Tern" title="Arctic Tern">Arctic Tern</a> holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year. Some species of tubenoses (<a href="Procellariiformes" webstripperwas="http://en.wikipedia.org/wiki/Procellariiformes" title="Procellariiformes">Procellariiformes</a>) such as <a href="Albatross" webstripperwas="http://en.wikipedia.org/wiki/Albatross" title="Albatross">albatrosses</a> circle the earth, flying over the southern oceans, while others such as <a href="Manx_Shearwaters" webstripperwas="http://en.wikipedia.org/wiki/Manx_Shearwaters" title="Manx Shearwaters" class="mw-redirect">Manx Shearwaters</a> migrate 14,000 km (8,700 mi) between their northern breeding grounds and the southern ocean. Shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas.</p>
<p>The timing of migration is controlled primarily by changes in day length. Migrating birds navigate using celestial cues from the sun and stars, the earth's magnetic field, and probably also mental maps. Migration has developed independently in different groups of birds and does not appear to require genetic change; some birds have acquired migratory behaviour since the last ice age.</p>
<table id="toc" class="toc">
<tr>
<td>
<div id="toctitle">
<h2>Contents</h2>
</div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#General_patterns"><span class="tocnumber">1</span> <span class="toctext">General patterns</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="#Historical_views"><span class="tocnumber">2</span> <span class="toctext">Historical views</span></a>
<ul>
<li class="toclevel-2 tocsection-3"><a href="#Swallow_migration_versus_hibernation"><span class="tocnumber">2.1</span> <span class="toctext">Swallow migration versus hibernation</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-4"><a href="#Long-distance_migration"><span class="tocnumber">3</span> <span class="toctext">Long-distance migration</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="#Short-distance_and_altitudinal_migration"><span class="tocnumber">4</span> <span class="toctext">Short-distance and altitudinal migration</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="#Irruptions_and_dispersal"><span class="tocnumber">5</span> <span class="toctext">Irruptions and dispersal</span></a></li>
<li class="toclevel-1 tocsection-7"><a href="#Physiology_and_control"><span class="tocnumber">6</span> <span class="toctext">Physiology and control</span></a>
<ul>
<li class="toclevel-2 tocsection-8"><a href="#Timing"><span class="tocnumber">6.1</span> <span class="toctext">Timing</span></a></li>
<li class="toclevel-2 tocsection-9"><a href="#Orientation_and_navigation"><span class="tocnumber">6.2</span> <span class="toctext">Orientation and navigation</span></a></li>
<li class="toclevel-2 tocsection-10"><a href="#Vagrancy"><span class="tocnumber">6.3</span> <span class="toctext">Vagrancy</span></a></li>
<li class="toclevel-2 tocsection-11"><a href="#Migration_conditioning"><span class="tocnumber">6.4</span> <span class="toctext">Migration conditioning</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-12"><a href="#Adaptations"><span class="tocnumber">7</span> <span class="toctext">Adaptations</span></a></li>
<li class="toclevel-1 tocsection-13"><a href="#Evolutionary_and_ecological_factors"><span class="tocnumber">8</span> <span class="toctext">Evolutionary and ecological factors</span></a>
<ul>
<li class="toclevel-2 tocsection-14"><a href="#Climate_change"><span class="tocnumber">8.1</span> <span class="toctext">Climate change</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-15"><a href="#Ecological_effects"><span class="tocnumber">9</span> <span class="toctext">Ecological effects</span></a></li>
<li class="toclevel-1 tocsection-16"><a href="#Study_techniques"><span class="tocnumber">10</span> <span class="toctext">Study techniques</span></a></li>
<li class="toclevel-1 tocsection-17"><a href="#Threats_and_conservation"><span class="tocnumber">11</span> <span class="toctext">Threats and conservation</span></a></li>
<li class="toclevel-1 tocsection-18"><a href="#See_also"><span class="tocnumber">12</span> <span class="toctext">See also</span></a></li>
<li class="toclevel-1 tocsection-19"><a href="#References"><span class="tocnumber">13</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-20"><a href="#Further_reading"><span class="tocnumber">14</span> <span class="toctext">Further reading</span></a></li>
<li class="toclevel-1 tocsection-21"><a href="#External_links"><span class="tocnumber">15</span> <span class="toctext">External links</span></a></li>
</ul>
</td>
</tr>
</table>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=1" title="Edit section: General patterns">edit</a>]</span> <span class="mw-headline" id="General_patterns">General patterns</span></h2>
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Flocks of birds assembling before migration southwards (probably <a href="Sturnus_vulgaris" webstripperwas="http://en.wikipedia.org/wiki/Sturnus_vulgaris" title="Sturnus vulgaris" class="mw-redirect">Sturnus vulgaris</a>)</div>
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<div class="thumbinner" style="width:222px;"><a href="File3AWaders_in_flight_Roebuck_Bay.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Waders_in_flight_Roebuck_Bay.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Waders_in_flight_Roebuck_Bay.jpg/220px-Waders_in_flight_Roebuck_Bay.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Waders_in_flight_Roebuck_Bay.jpg/220px-Waders_in_flight_Roebuck_Bay.jpg" width="220" height="147" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Waders_in_flight_Roebuck_Bay.jpg/330px-Waders_in_flight_Roebuck_Bay.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Waders_in_flight_Roebuck_Bay.jpg/440px-Waders_in_flight_Roebuck_Bay.jpg 2x" /></a>
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Migrating waders in <a href="Roebuck_Bay" webstripperwas="http://en.wikipedia.org/wiki/Roebuck_Bay" title="Roebuck Bay">Roebuck Bay</a>, Western Australia</div>
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<p>Migration is the regular seasonal movement, often north and south, undertaken by many species of <a href="Bird.html" webstripperwas="/wiki/Bird" title="Bird">birds</a>. Bird movements include those made in response to changes in food availability, habitat, or weather. Sometimes, journeys are not termed "true migration" because they are irregular (nomadism, invasions, irruptions) or in only one direction (dispersal, movement of young away from natal area). Migration is marked by its annual seasonality.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span>[</span>1<span>]</span></a></sup> Non-migratory birds are said to be resident or sedentary. Approximately 1800 of the world's 10,000 bird species are long-distance migrants.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span>[</span>2<span>]</span></a></sup></p>
<p>Many bird populations migrate long distances along a <a href="Flyway" webstripperwas="http://en.wikipedia.org/wiki/Flyway" title="Flyway">flyway</a>. The most common pattern involves flying north in the spring to breed in the temperate or <a href="Arctic" webstripperwas="http://en.wikipedia.org/wiki/Arctic" title="Arctic">Arctic</a> summer and returning in the autumn to wintering grounds in warmer regions to the south. Of course, in the Southern Hemisphere the directions are reversed, but there is less land area in the far South to support long-distance migration.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>The primary motivation for migration appears to be food; for example, some hummingbirds choose not to migrate if fed through the winter. Also, the longer days of the northern summer provide extended time for <a href="Breeding_in_the_wild" webstripperwas="http://en.wikipedia.org/wiki/Breeding_in_the_wild" title="Breeding in the wild">breeding</a> birds to feed their young. This helps <a href="Diurnality" webstripperwas="http://en.wikipedia.org/wiki/Diurnality" title="Diurnality">diurnal</a> birds to produce larger <a href="Clutch_(eggs)" webstripperwas="http://en.wikipedia.org/wiki/Clutch_(eggs)" title="Clutch (eggs)">clutches</a> than related non-migratory species that remain in the tropics. As the days shorten in autumn, the birds return to warmer regions where the available food supply varies little with the season.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>These advantages offset the high stress, physical exertion costs, and other risks of the migration such as predation. Predation can be heightened during migration: the <a href="Eleonora$27s_Falcon" webstripperwas="http://en.wikipedia.org/wiki/Eleonora%27s_Falcon" title="Eleonora's Falcon">Eleonora's Falcon</a>, which breeds on <a href="Mediterranean_Sea" webstripperwas="http://en.wikipedia.org/wiki/Mediterranean_Sea" title="Mediterranean Sea">Mediterranean</a> islands, has a very late breeding season, coordinated with the autumn passage of southbound <a href="Passerine.html" webstripperwas="/wiki/Passerine" title="Passerine">passerine</a> migrants, which it feeds to its young. A similar strategy is adopted by the <a href="Greater_Noctule_bat" webstripperwas="http://en.wikipedia.org/wiki/Greater_Noctule_bat" title="Greater Noctule bat" class="mw-redirect">Greater Noctule bat</a>, which preys on nocturnal passerine migrants.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span>[</span>3<span>]</span></a></sup><sup id="cite_ref-bats_4-0" class="reference"><a href="#cite_note-bats-4"><span>[</span>4<span>]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span>[</span>5<span>]</span></a></sup> The higher concentrations of migrating birds at stopover sites make them prone to parasites and pathogens, which require a heightened immune response.<sup id="cite_ref-newton_6-0" class="reference"><a href="#cite_note-newton-6"><span>[</span>6<span>]</span></a></sup></p>
<p>Within a species not all populations may be migratory; this is known as "partial migration". Partial migration is very common in the southern continents; in Australia, 44% of non-passerine birds and 32% of passerine species are partially migratory.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span>[</span>7<span>]</span></a></sup> In some species, the population at higher latitudes tends to be migratory and will often winter at lower latitude. The migrating birds bypass the latitudes where other populations may be sedentary, where suitable wintering habitats may already be occupied. This is an example of <i>leap-frog migration</i>.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span>[</span>8<span>]</span></a></sup> Many fully migratory species show leap-frog migration (birds that nest at higher latitudes spend the winter at lower latitudes), and many show the alternative, "chain migration" where populations 'slide' more evenly North and South without reversing order.</p>
<p>Within a population, it is common for different ages and/or sexes to have different patterns of timing and distance. Female <a href="Common_Chaffinch" webstripperwas="http://en.wikipedia.org/wiki/Common_Chaffinch" title="Common Chaffinch">Chaffinches</a> in Eastern Fennoscandia migrate earlier in the autumn than males do.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span>[</span>9<span>]</span></a></sup></p>
<p>Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes termed <a href="Flyway" webstripperwas="http://en.wikipedia.org/wiki/Flyway" title="Flyway">flyways</a>. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often different.<sup id="cite_ref-newton_6-1" class="reference"><a href="#cite_note-newton-6"><span>[</span>6<span>]</span></a></sup> A common pattern in North America is clockwise migration, where birds flying North tend to be further West, and flying South tend to shift Eastwards.</p>
<p>Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 12–20% of the energy they would need to fly alone.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span>[</span>10<span>]</span></a></sup><sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span>[</span>11<span>]</span></a></sup> Red Knots <i>Calidris canutus</i> and Dunlins <i>Calidris alpina</i> were found in radar studies to fly 5 km per hour faster in flocks than when they were flying alone.<sup id="cite_ref-newton_6-2" class="reference"><a href="#cite_note-newton-6"><span>[</span>6<span>]</span></a></sup></p>
<p>Birds fly at varying altitudes during migration. An expedition to <a href="Mount_Everest" webstripperwas="http://en.wikipedia.org/wiki/Mount_Everest" title="Mount Everest">Mt. Everest</a> found skeletons of <a href="Northern_Pintail" webstripperwas="http://en.wikipedia.org/wiki/Northern_Pintail" title="Northern Pintail">Pintail</a> and <a href="Black-tailed_Godwit" webstripperwas="http://en.wikipedia.org/wiki/Black-tailed_Godwit" title="Black-tailed Godwit">Black-tailed Godwit</a> at 5000 m (16,400 ft) on the <a href="Khumbu_Glacier" webstripperwas="http://en.wikipedia.org/wiki/Khumbu_Glacier" title="Khumbu Glacier">Khumbu Glacier</a>.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span>[</span>12<span>]</span></a></sup> <a href="Bar-headed_Goose" webstripperwas="http://en.wikipedia.org/wiki/Bar-headed_Goose" title="Bar-headed Goose">Bar-headed Geese</a> have been recorded by GPS flying at up to 6,540 metres while crossing the Himalayas, at the same time engaging in the highest rates of climb to altitude for any bird. Anecdotal reports of them flying much higher have yet to be corroborated with any direct evidence.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span>[</span>13<span>]</span></a></sup> Seabirds fly low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span>[</span>14<span>]</span></a></sup><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span>[</span>15<span>]</span></a></sup> However most bird migration is in the range of 150 m (500 ft) to 600 m (2000 ft). Bird-hit aviation records from the United States show most collisions occur below 600 m (2000 ft) and almost none above 1800 m (6000 ft).<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span>[</span>16<span>]</span></a></sup></p>
<p>Bird migration is not limited to birds that can fly. Most species of <a href="Penguin" webstripperwas="http://en.wikipedia.org/wiki/Penguin" title="Penguin">penguin</a> migrate by swimming. These routes can cover over 1000 km. Blue Grouse <i>Dendragapus obscurus</i> perform altitudinal migration mostly by walking. <a href="Emus" webstripperwas="http://en.wikipedia.org/wiki/Emus" title="Emus" class="mw-redirect">Emus</a> in <a href="Australia" webstripperwas="http://en.wikipedia.org/wiki/Australia" title="Australia">Australia</a> have been observed to undertake long-distance movements on foot during droughts.<sup id="cite_ref-newton_6-3" class="reference"><a href="#cite_note-newton-6"><span>[</span>6<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=2" title="Edit section: Historical views">edit</a>]</span> <span class="mw-headline" id="Historical_views">Historical views</span></h2>
<p>Records of bird migration were made 3,000 years ago by the <a href="Ancient_Greece" webstripperwas="http://en.wikipedia.org/wiki/Ancient_Greece" title="Ancient Greece">Ancient Greek</a> writers <a href="Hesiod" webstripperwas="http://en.wikipedia.org/wiki/Hesiod" title="Hesiod">Hesiod</a>, <a href="Homer" webstripperwas="http://en.wikipedia.org/wiki/Homer" title="Homer">Homer</a>, <a href="Herodotus" webstripperwas="http://en.wikipedia.org/wiki/Herodotus" title="Herodotus">Herodotus</a> and <a href="Aristotle.html" webstripperwas="/wiki/Aristotle" title="Aristotle">Aristotle</a>. The Bible also notes migrations, as in the <a href="Book_of_Job" webstripperwas="http://en.wikipedia.org/wiki/Book_of_Job" title="Book of Job">Book of Job</a> (<a rel="nofollow" class="external text" href="http://bibref.hebtools.com?book=%20Job&verse=39:26&src=KJV" >39:26</a>), where the inquiry is made: "Doth the hawk fly by Thy wisdom and stretch her wings toward the south?" The author of <a href="Book_of_Jeremiah" webstripperwas="http://en.wikipedia.org/wiki/Book_of_Jeremiah" title="Book of Jeremiah">Jeremiah</a> (<a rel="nofollow" class="external text" href="http://bibref.hebtools.com?book=%20Jeremiah&verse=8:7&src=KJV" >8:7</a>) wrote: "The <a href="Stork" webstripperwas="http://en.wikipedia.org/wiki/Stork" title="Stork">stork</a> in the heavens knoweth her appointed time; and the <a href="European_Turtle_Dove" webstripperwas="http://en.wikipedia.org/wiki/European_Turtle_Dove" title="European Turtle Dove" class="mw-redirect">turtledove</a>, and the <a href="Crane_(bird)" webstripperwas="http://en.wikipedia.org/wiki/Crane_(bird)" title="Crane (bird)">crane</a>, and the <a href="Swallow" webstripperwas="http://en.wikipedia.org/wiki/Swallow" title="Swallow">swallow</a>, observe the time of their coming."</p>
<p>Aristotle noted that cranes traveled from the steppes of <a href="Scythia" webstripperwas="http://en.wikipedia.org/wiki/Scythia" title="Scythia">Scythia</a> to marshes at the headwaters of the <a href="Nile" webstripperwas="http://en.wikipedia.org/wiki/Nile" title="Nile">Nile</a>. <a href="Pliny_the_Elder.html" webstripperwas="/wiki/Pliny_the_Elder" title="Pliny the Elder">Pliny the Elder</a>, in his <i><a href="Natural_History_(Pliny).html" webstripperwas="/wiki/Natural_History_(Pliny)" title="Natural History (Pliny)">Historia Naturalis</a></i>, repeats Aristotle's observations.<sup id="cite_ref-Lincoln_17-0" class="reference"><a href="#cite_note-Lincoln-17"><span>[</span>17<span>]</span></a></sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=3" title="Edit section: Swallow migration versus hibernation">edit</a>]</span> <span class="mw-headline" id="Swallow_migration_versus_hibernation">Swallow migration versus hibernation</span></h3>
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<div class="thumbinner" style="width:222px;"><a href="File3AAkrotiri_spring.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Akrotiri_spring.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Akrotiri_spring.jpg/220px-Akrotiri_spring.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Akrotiri_spring.jpg/220px-Akrotiri_spring.jpg" width="220" height="148" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Akrotiri_spring.jpg/330px-Akrotiri_spring.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Akrotiri_spring.jpg/440px-Akrotiri_spring.jpg 2x" /></a>
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<div class="magnify"><a href="File3AAkrotiri_spring.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Akrotiri_spring.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
<a href="Minoan" webstripperwas="http://en.wikipedia.org/wiki/Minoan" title="Minoan">Minoan</a> <a href="Fresco" webstripperwas="http://en.wikipedia.org/wiki/Fresco" title="Fresco">fresco</a> of <a href="Swallow" webstripperwas="http://en.wikipedia.org/wiki/Swallow" title="Swallow">swallows</a> in springtime at <a href="Akrotiri" webstripperwas="http://en.wikipedia.org/wiki/Akrotiri" title="Akrotiri" class="mw-redirect">Akrotiri</a>, c. 1500 BC</div>
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<p>Aristotle however suggested that swallows and other birds hibernated. This belief persisted as late as 1878, when <a href="Elliott_Coues" webstripperwas="http://en.wikipedia.org/wiki/Elliott_Coues" title="Elliott Coues">Elliott Coues</a> listed the titles of no less than 182 papers dealing with the hibernation of swallows. Even the "highly observant"<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span>[</span>18<span>]</span></a></sup> <a href="Gilbert_White" webstripperwas="http://en.wikipedia.org/wiki/Gilbert_White" title="Gilbert White">Gilbert White</a>, in his posthumously published 1789 <i><a href="The_Natural_History_of_Selborne" webstripperwas="http://en.wikipedia.org/wiki/The_Natural_History_of_Selborne" title="The Natural History of Selborne" class="mw-redirect">The Natural History of Selborne</a></i>, quoted a man's story about swallows being found in a chalk cliff collapse "while he was a schoolboy at Brighthelmstone", though the man denied being an eyewitness.<sup id="cite_ref-GilbertWhite1_19-0" class="reference"><a href="#cite_note-GilbertWhite1-19"><span>[</span>19<span>]</span></a></sup> However, he also writes that "as to swallows being found in a torpid state during the winter in the Isle of Wight or any part of this country, I never heard any such account worth attending to",<sup id="cite_ref-GilbertWhite1_19-1" class="reference"><a href="#cite_note-GilbertWhite1-19"><span>[</span>19<span>]</span></a></sup> and that if early swallows "happen to find frost and snow they immediately withdraw for a time—a circumstance this much more in favour of hiding than migration", since he doubts they would "return for a week or two to warmer latitudes".<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span>[</span>20<span>]</span></a></sup></p>
<p>It was not until the end of the eighteenth century that migration as an explanation for the winter disappearance of birds from northern climes was accepted.<sup id="cite_ref-Lincoln_17-1" class="reference"><a href="#cite_note-Lincoln-17"><span>[</span>17<span>]</span></a></sup> <a href="Thomas_Bewick" webstripperwas="http://en.wikipedia.org/wiki/Thomas_Bewick" title="Thomas Bewick">Thomas Bewick</a>'s <i><a href="A_History_of_British_Birds" webstripperwas="http://en.wikipedia.org/wiki/A_History_of_British_Birds" title="A History of British Birds">A History of British Birds</a></i> (Volume 1, 1797) states the situation as follows:</p>
<blockquote class="templatequote">
<div class="Bug6200">Swallows frequently roost at night, after they begin to congregate, by the sides of rivers and pools, from which circumstance it has been erroneously supposed that they retire into the water.</div>
<div class="templatequotecite">—Bewick<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span>[</span>21<span>]</span></a></sup></div>
</blockquote>
<p>Bewick then describes an experiment which succeeded in keeping swallows alive in Britain for several years, where they remained warm and dry through the winters. He concludes:</p>
<blockquote class="templatequote">
<div class="Bug6200">These experiments have since been amply confirmed by ... M. Natterer, of Vienna ... and the result clearly proves, what is in fact now admitted on all hands, that Swallows do not in any material instance differ from other birds in their nature and propensities [for life in the air]; but that they leave us when this country can no longer furnish them with a supply of their proper and natural food...</div>
<div class="templatequotecite">—Bewick<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span>[</span>22<span>]</span></a></sup></div>
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<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=4" title="Edit section: Long-distance migration">edit</a>]</span> <span class="mw-headline" id="Long-distance_migration">Long-distance migration</span></h2>
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<div class="thumbinner" style="width:222px;"><a href="File3ASwainsonThrush23.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:SwainsonThrush23.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/d/d6/SwainsonThrush23.jpg/220px-SwainsonThrush23.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/SwainsonThrush23.jpg/220px-SwainsonThrush23.jpg" width="220" height="128" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/d/d6/SwainsonThrush23.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/d/d6/SwainsonThrush23.jpg 2x" /></a>
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<a href="Swainson$27s_Thrush" webstripperwas="http://en.wikipedia.org/wiki/Swainson%27s_Thrush" title="Swainson's Thrush">Swainson's Thrush</a></div>
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<div class="thumbinner" style="width:222px;"><a href="File3ANorthern_Pintail.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Northern_Pintail.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/2/22/Northern_Pintail.jpg/220px-Northern_Pintail.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Northern_Pintail.jpg/220px-Northern_Pintail.jpg" width="220" height="126" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Northern_Pintail.jpg/330px-Northern_Pintail.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/22/Northern_Pintail.jpg/440px-Northern_Pintail.jpg 2x" /></a>
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<div class="magnify"><a href="File3ANorthern_Pintail.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Northern_Pintail.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
<a href="Northern_Pintail" webstripperwas="http://en.wikipedia.org/wiki/Northern_Pintail" title="Northern Pintail">Northern Pintail</a></div>
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<p>The typical image of migration is of northern landbirds, such as <a href="Swallow" webstripperwas="http://en.wikipedia.org/wiki/Swallow" title="Swallow">swallows</a> and birds of prey, making long flights to the tropics. However, many Holarctic <a href="Wildfowl" webstripperwas="http://en.wikipedia.org/wiki/Wildfowl" title="Wildfowl" class="mw-redirect">wildfowl</a> and <a href="Fringillidae" webstripperwas="http://en.wikipedia.org/wiki/Fringillidae" title="Fringillidae" class="mw-redirect">finch</a> species winter in the <a href="North_Temperate_Zone" webstripperwas="http://en.wikipedia.org/wiki/North_Temperate_Zone" title="North Temperate Zone" class="mw-redirect">North Temperate Zone</a>, but in regions with milder winters than their summer breeding grounds. For example, the <a href="Pink-footed_goose" webstripperwas="http://en.wikipedia.org/wiki/Pink-footed_goose" title="Pink-footed goose" class="mw-redirect">pink-footed goose</a> migrates from <a href="Iceland.html" webstripperwas="/wiki/Iceland" title="Iceland">Iceland</a> to <a href="Great_Britain" webstripperwas="http://en.wikipedia.org/wiki/Great_Britain" title="Great Britain">Britain</a> and neighbouring countries, whilst the <a href="Dark-Eyed_Junco" webstripperwas="http://en.wikipedia.org/wiki/Dark-Eyed_Junco" title="Dark-Eyed Junco" class="mw-redirect">Dark-Eyed Junco</a> migrates from <a href="Subarctic_climate" webstripperwas="http://en.wikipedia.org/wiki/Subarctic_climate" title="Subarctic climate">subarctic</a> and <a href="Tundra_climate" webstripperwas="http://en.wikipedia.org/wiki/Tundra_climate" title="Tundra climate" class="mw-redirect">arctic climates</a> to the contiguous United States<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span>[</span>23<span>]</span></a></sup> and the American Goldfinch from taiga to wintering grounds extending from the <a href="Southern_United_States" webstripperwas="http://en.wikipedia.org/wiki/Southern_United_States" title="Southern United States">American South</a> northwestward to <a href="Western_Oregon" webstripperwas="http://en.wikipedia.org/wiki/Western_Oregon" title="Western Oregon">Western Oregon</a>.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span>[</span>24<span>]</span></a></sup> Migratory routes and wintering grounds are traditional and learned by young during their first migration with their parents. Some ducks, such as the <a href="Garganey" webstripperwas="http://en.wikipedia.org/wiki/Garganey" title="Garganey">Garganey</a>, move completely or partially into the tropics. The <a href="European_pied_flycatcher" webstripperwas="http://en.wikipedia.org/wiki/European_pied_flycatcher" title="European pied flycatcher" class="mw-redirect">European pied flycatcher</a> also follows this migratory trend, breeding in Asia and Europe and wintering in Africa.</p>
<p>The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites is a barrier to may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, <a href="Brent_Goose" webstripperwas="http://en.wikipedia.org/wiki/Brent_Goose" title="Brent Goose" class="mw-redirect">Brent Geese</a> migrating from the <a href="Taymyr_Peninsula" webstripperwas="http://en.wikipedia.org/wiki/Taymyr_Peninsula" title="Taymyr Peninsula">Taymyr Peninsula</a> to the <a href="Wadden_Sea" webstripperwas="http://en.wikipedia.org/wiki/Wadden_Sea" title="Wadden Sea">Wadden Sea</a> travel via the <a href="White_Sea" webstripperwas="http://en.wikipedia.org/wiki/White_Sea" title="White Sea">White Sea</a> coast and the <a href="Baltic_Sea" webstripperwas="http://en.wikipedia.org/wiki/Baltic_Sea" title="Baltic Sea">Baltic Sea</a> rather than directly across the <a href="Arctic_Ocean" webstripperwas="http://en.wikipedia.org/wiki/Arctic_Ocean" title="Arctic Ocean">Arctic Ocean</a> and northern <a href="Scandinavia" webstripperwas="http://en.wikipedia.org/wiki/Scandinavia" title="Scandinavia">Scandinavia</a>.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
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<div class="thumbinner" style="width:222px;"><a href="File3ABartailedGodwit24.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:BartailedGodwit24.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/5/5a/BartailedGodwit24.jpg/220px-BartailedGodwit24.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/BartailedGodwit24.jpg/220px-BartailedGodwit24.jpg" width="220" height="149" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5a/BartailedGodwit24.jpg/330px-BartailedGodwit24.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5a/BartailedGodwit24.jpg/440px-BartailedGodwit24.jpg 2x" /></a>
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<div class="magnify"><a href="File3ABartailedGodwit24.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:BartailedGodwit24.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
<a href="Bar-tailed_Godwit" webstripperwas="http://en.wikipedia.org/wiki/Bar-tailed_Godwit" title="Bar-tailed Godwit">Bar-tailed Godwit</a></div>
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<p>A similar situation occurs with <a href="Wader" webstripperwas="http://en.wikipedia.org/wiki/Wader" title="Wader">waders</a> (called "shorebirds" in North America). Many species, such as <a href="Dunlin" webstripperwas="http://en.wikipedia.org/wiki/Dunlin" title="Dunlin">Dunlin</a> and <a href="Western_Sandpiper" webstripperwas="http://en.wikipedia.org/wiki/Western_Sandpiper" title="Western Sandpiper">Western Sandpiper</a>, undertake long movements from their Arctic breeding grounds to warmer locations in the same hemisphere, but others such as <a href="Semipalmated_Sandpiper" webstripperwas="http://en.wikipedia.org/wiki/Semipalmated_Sandpiper" title="Semipalmated Sandpiper">Semipalmated Sandpiper</a> travel longer distances to the tropics in the Southern Hemisphere. Like the large and powerful wildfowl, the waders are strong fliers. This means that birds wintering in temperate regions have the capacity to make further shorter movements in the event of particularly inclement weather.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>For some species of waders, migration success depends on the availability of certain key food resources at stopover points along the migration route. This gives the migrants an opportunity to "refuel" for the next leg of the voyage. Some examples of important stopover locations are the <a href="Bay_of_Fundy" webstripperwas="http://en.wikipedia.org/wiki/Bay_of_Fundy" title="Bay of Fundy">Bay of Fundy</a> and <a href="Delaware_River" webstripperwas="http://en.wikipedia.org/wiki/Delaware_River" title="Delaware River">Delaware Bay</a>.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Some <a href="Bar-tailed_Godwit" webstripperwas="http://en.wikipedia.org/wiki/Bar-tailed_Godwit" title="Bar-tailed Godwit">Bar-tailed Godwits</a> have the longest known non-stop flight of any migrant, flying 11,000 km from <a href="Alaska" webstripperwas="http://en.wikipedia.org/wiki/Alaska" title="Alaska">Alaska</a> to their <a href="New_Zealand" webstripperwas="http://en.wikipedia.org/wiki/New_Zealand" title="New Zealand">New Zealand</a> non-breeding areas.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span>[</span>25<span>]</span></a></sup> Prior to migration, 55 percent of their bodyweight is stored fat to fuel this uninterrupted journey.</p>
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<div class="thumbinner" style="width:222px;"><a href="File3AArctic_terns.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Arctic_terns.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/9/96/Arctic_terns.jpg/220px-Arctic_terns.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/9/96/Arctic_terns.jpg/220px-Arctic_terns.jpg" width="220" height="220" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/96/Arctic_terns.jpg/330px-Arctic_terns.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/96/Arctic_terns.jpg/440px-Arctic_terns.jpg 2x" /></a>
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<div class="magnify"><a href="File3AArctic_terns.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Arctic_terns.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
<a href="Arctic_Tern" webstripperwas="http://en.wikipedia.org/wiki/Arctic_Tern" title="Arctic Tern">Arctic Terns</a></div>
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<p><a href="Seabird" webstripperwas="http://en.wikipedia.org/wiki/Seabird" title="Seabird">Seabird</a> migration is similar in pattern to those of the waders and waterfowl. Some, such as the <a href="Black_Guillemot" webstripperwas="http://en.wikipedia.org/wiki/Black_Guillemot" title="Black Guillemot">Black Guillemot</a> and some <a href="Gull" webstripperwas="http://en.wikipedia.org/wiki/Gull" title="Gull">gulls</a>, are quite sedentary; others, such as most <a href="Tern" webstripperwas="http://en.wikipedia.org/wiki/Tern" title="Tern">terns</a> and <a href="Auk" webstripperwas="http://en.wikipedia.org/wiki/Auk" title="Auk">auks</a> breeding in the temperate northern hemisphere, move varying distances south in the northern winter. The <a href="Arctic_Tern" webstripperwas="http://en.wikipedia.org/wiki/Arctic_Tern" title="Arctic Tern">Arctic Tern</a> has the longest-distance migration of any bird, and sees more daylight than any other, moving from its Arctic breeding grounds to the Antarctic non-breeding areas. One Arctic Tern, <a href="Bird_ringing" webstripperwas="http://en.wikipedia.org/wiki/Bird_ringing" title="Bird ringing">ringed</a> (banded) as a chick on the <a href="Farne_Islands" webstripperwas="http://en.wikipedia.org/wiki/Farne_Islands" title="Farne Islands">Farne Islands</a> off the <a href="Great_Britain" webstripperwas="http://en.wikipedia.org/wiki/Great_Britain" title="Great Britain">British</a> east coast, reached <a href="Melbourne" webstripperwas="http://en.wikipedia.org/wiki/Melbourne" title="Melbourne">Melbourne</a>, <a href="Australia" webstripperwas="http://en.wikipedia.org/wiki/Australia" title="Australia">Australia</a> in just three months from fledging, a sea journey of over 22,000 km (14,000 mi). A few seabirds, such as <a href="Wilson$27s_Petrel" webstripperwas="http://en.wikipedia.org/wiki/Wilson%27s_Petrel" title="Wilson's Petrel" class="mw-redirect">Wilson's Petrel</a> and <a href="Great_Shearwater" webstripperwas="http://en.wikipedia.org/wiki/Great_Shearwater" title="Great Shearwater">Great Shearwater</a>, breed in the southern hemisphere and migrate north in the southern winter. Seabirds have the additional advantage of being able to feed during migration over open waters.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>The most pelagic species, mainly in the 'tubenose' order <a href="Procellariiformes" webstripperwas="http://en.wikipedia.org/wiki/Procellariiformes" title="Procellariiformes">Procellariiformes</a>, are great wanderers, and the <a href="Albatross" webstripperwas="http://en.wikipedia.org/wiki/Albatross" title="Albatross">albatrosses</a> of the southern oceans may circle the globe as they ride the "roaring forties" outside the breeding season. The tubenoses spread widely over large areas of open ocean, but congregate when food becomes available. Many are also among the longest-distance migrants; <a href="Sooty_Shearwater" webstripperwas="http://en.wikipedia.org/wiki/Sooty_Shearwater" title="Sooty Shearwater">Sooty Shearwaters</a> nesting on the <a href="Falkland_Islands" webstripperwas="http://en.wikipedia.org/wiki/Falkland_Islands" title="Falkland Islands">Falkland Islands</a> migrate 14,000 km (8,700 mi) between the breeding colony and the <a href="Atlantic_Ocean" webstripperwas="http://en.wikipedia.org/wiki/Atlantic_Ocean" title="Atlantic Ocean">North Atlantic Ocean</a> off <a href="Norway" webstripperwas="http://en.wikipedia.org/wiki/Norway" title="Norway">Norway</a>. Some <a href="Manx_Shearwater" webstripperwas="http://en.wikipedia.org/wiki/Manx_Shearwater" title="Manx Shearwater">Manx Shearwaters</a> do this same journey in reverse. As they are long-lived birds, they may cover enormous distances during their lives; one record-breaking Manx Shearwater is calculated to have flown 8 million km (5 million miles) during its over-50 year lifespan.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span>[</span>26<span>]</span></a></sup></p>
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<div class="thumbinner" style="width:222px;"><a href="File3AVulture_19o05.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Vulture_19o05.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Vulture_19o05.jpg/220px-Vulture_19o05.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Vulture_19o05.jpg/220px-Vulture_19o05.jpg" width="220" height="159" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Vulture_19o05.jpg/330px-Vulture_19o05.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Vulture_19o05.jpg/440px-Vulture_19o05.jpg 2x" /></a>
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<div class="magnify"><a href="File3AVulture_19o05.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Vulture_19o05.jpg" class="internal" title="Enlarge"><img src="bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" webstripperwas="//bits.wikimedia.org/static-1.22wmf1/skins/common/images/magnify-clip.png" width="15" height="11" alt="" /></a></div>
<a href="Griffon_Vulture" webstripperwas="http://en.wikipedia.org/wiki/Griffon_Vulture" title="Griffon Vulture">Griffon Vulture</a> soaring</div>
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<p>Some large broad-winged birds rely on <a href="Thermal" webstripperwas="http://en.wikipedia.org/wiki/Thermal" title="Thermal">thermal columns</a> of rising hot air to enable them to soar. These include many <a href="Bird_of_prey" webstripperwas="http://en.wikipedia.org/wiki/Bird_of_prey" title="Bird of prey">birds of prey</a> such as <a href="Vulture" webstripperwas="http://en.wikipedia.org/wiki/Vulture" title="Vulture">vultures</a>, <a href="Eagle" webstripperwas="http://en.wikipedia.org/wiki/Eagle" title="Eagle">eagles</a>, and <a href="Buzzard" webstripperwas="http://en.wikipedia.org/wiki/Buzzard" title="Buzzard">buzzards</a>, but also <a href="Stork" webstripperwas="http://en.wikipedia.org/wiki/Stork" title="Stork">storks</a>. These birds migrate in the daytime. Migratory species in these groups have great difficulty crossing large bodies of water, since thermals only form over land, and these birds cannot maintain active flight for long distances. Mediterranean and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large <a href="Bird_of_prey" webstripperwas="http://en.wikipedia.org/wiki/Bird_of_prey" title="Bird of prey">raptors</a> and storks pass through areas such as <a href="Gibraltar" webstripperwas="http://en.wikipedia.org/wiki/Gibraltar" title="Gibraltar">Gibraltar</a>, <a href="Falsterbo" webstripperwas="http://en.wikipedia.org/wiki/Falsterbo" title="Falsterbo">Falsterbo</a>, and the <a href="Bosphorus" webstripperwas="http://en.wikipedia.org/wiki/Bosphorus" title="Bosphorus">Bosphorus</a> at migration times. More common species, such as the <a href="European_Honey_Buzzard" webstripperwas="http://en.wikipedia.org/wiki/European_Honey_Buzzard" title="European Honey Buzzard">European Honey Buzzard</a>, can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants. This is a notable factor in the <a href="Central_America" webstripperwas="http://en.wikipedia.org/wiki/Central_America" title="Central America">Central American</a> migratory bottleneck. Batumi bottleneck in the Caucasus is one of the heaviest migratory funnels on earth. Avoiding flying over the Black Sea surface and across high mountains, hundreds of thousands of soaring birds funnel through an area around the city of <a href="Batumi" webstripperwas="http://en.wikipedia.org/wiki/Batumi" title="Batumi">Batumi</a>, Georgia.<sup id="cite_ref-Gavashelishvili11_27-0" class="reference"><a href="#cite_note-Gavashelishvili11-27"><span>[</span>27<span>]</span></a></sup> It has been suggested <sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span>[</span>28<span>]</span></a></sup> that birds of prey (such as Honey Buzzards) which migrate using thermals may benefit from losing 10 to 20% of their weight and that this may explain why they forage less on migration than do smaller birds of prey with more active flight such as Falcons, Hawks and Harriers.</p>
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<div class="thumbinner" style="width:222px;"><a href="File3ARubythroathummer65.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Rubythroathummer65.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/8/87/Rubythroathummer65.jpg/220px-Rubythroathummer65.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Rubythroathummer65.jpg/220px-Rubythroathummer65.jpg" width="220" height="202" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/8/87/Rubythroathummer65.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/8/87/Rubythroathummer65.jpg 2x" /></a>
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<a href="Ruby-throated_Hummingbird" webstripperwas="http://en.wikipedia.org/wiki/Ruby-throated_Hummingbird" title="Ruby-throated Hummingbird">Ruby-throated Hummingbird</a></div>
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<p>Many of the smaller insectivorous birds including the <a href="Warbler" webstripperwas="http://en.wikipedia.org/wiki/Warbler" title="Warbler">warblers</a>, <a href="Hummingbird" webstripperwas="http://en.wikipedia.org/wiki/Hummingbird" title="Hummingbird">hummingbirds</a> and <a href="Old_World_flycatcher" webstripperwas="http://en.wikipedia.org/wiki/Old_World_flycatcher" title="Old World flycatcher">flycatchers</a> migrate large distances, usually at night. They land in the morning and may feed for a few days before resuming their migration. The birds are referred to as <i>passage migrants</i> in the regions where they occur for short durations between the origin and destination.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span>[</span>29<span>]</span></a></sup></p>
<p>Nocturnal migrants minimize predation, avoid overheating, and feed during the day.<sup id="cite_ref-Lincoln_17-2" class="reference"><a href="#cite_note-Lincoln-17"><span>[</span>17<span>]</span></a></sup> One cost of nocturnal migration is the loss of sleep. Migrants may be able to alter their quality of sleep to compensate for the loss.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span>[</span>30<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=5" title="Edit section: Short-distance and altitudinal migration">edit</a>]</span> <span class="mw-headline" id="Short-distance_and_altitudinal_migration">Short-distance and altitudinal migration</span></h2>
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<div class="thumbinner" style="width:222px;"><a href="File3ACedar_Waxwing-27527-1.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Cedar_Waxwing-27527-1.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/2/22/Cedar_Waxwing-27527-1.jpg/220px-Cedar_Waxwing-27527-1.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Cedar_Waxwing-27527-1.jpg/220px-Cedar_Waxwing-27527-1.jpg" width="220" height="165" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Cedar_Waxwing-27527-1.jpg/330px-Cedar_Waxwing-27527-1.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/22/Cedar_Waxwing-27527-1.jpg/440px-Cedar_Waxwing-27527-1.jpg 2x" /></a>
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<a href="Cedar_Waxwing" webstripperwas="http://en.wikipedia.org/wiki/Cedar_Waxwing" title="Cedar Waxwing">Cedar Waxwing</a></div>
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<p>Many long-distance migrants appear to be genetically programmed to respond to changing day length. Species that move short distances, however, may not need such a timing mechanism, and may move in response to local weather conditions. Thus mountain and moorland breeders, such as <a href="Wallcreeper" webstripperwas="http://en.wikipedia.org/wiki/Wallcreeper" title="Wallcreeper">Wallcreeper</a> and <a href="White-throated_Dipper" webstripperwas="http://en.wikipedia.org/wiki/White-throated_Dipper" title="White-throated Dipper">White-throated Dipper</a>, may move only altitudinally to escape the cold higher ground. Other species such as <a href="Merlin_(bird)" webstripperwas="http://en.wikipedia.org/wiki/Merlin_(bird)" title="Merlin (bird)">Merlin</a> and <a href="Skylark" webstripperwas="http://en.wikipedia.org/wiki/Skylark" title="Skylark" class="mw-redirect">Skylark</a> will move further to the coast or to a more southerly region. Species like the <a href="Common_Chaffinch" webstripperwas="http://en.wikipedia.org/wiki/Common_Chaffinch" title="Common Chaffinch">Common Chaffinch</a> are not migratory in <a href="Great_Britain" webstripperwas="http://en.wikipedia.org/wiki/Great_Britain" title="Great Britain">Britain</a>, but move south or to <a href="Ireland" webstripperwas="http://en.wikipedia.org/wiki/Ireland" title="Ireland">Ireland</a> in very cold weather.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Short-distance passerine migrants have two evolutionary origins. Those that have long-distance migrants in the same family, such as the <a href="Common_Chiffchaff" webstripperwas="http://en.wikipedia.org/wiki/Common_Chiffchaff" title="Common Chiffchaff">Common Chiffchaff</a>, are species of southern hemisphere origins that have progressively shortened their return migration to stay in the northern hemisphere.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span>[</span>31<span>]</span></a></sup></p>
<p>Species that have no long-distance migratory relatives, such as the <a href="Waxwing" webstripperwas="http://en.wikipedia.org/wiki/Waxwing" title="Waxwing">waxwings</a>, are effectively moving in response to winter weather and the loss of their usual winter food, rather than enhanced breeding opportunities.<sup id="cite_ref-CockerWaxwing_32-0" class="reference"><a href="#cite_note-CockerWaxwing-32"><span>[</span>32<span>]</span></a></sup></p>
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<a href="Woodland_Kingfisher" webstripperwas="http://en.wikipedia.org/wiki/Woodland_Kingfisher" title="Woodland Kingfisher">Woodland Kingfisher</a></div>
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<p>In the tropics there is little variation in the length of day throughout the year, and it is always warm enough for a food supply (although because of competition, there may not be enough food for every bird). Migration within the tropics has been far less studied than in the temperate zones. It was once assumed that tropical birds were mostly sedentary; however, altitudinal migration and other within-tropics movements appear to be surprisingly common.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (September 2011)">citation needed</span></a></i>]</sup> Many tropical regions have wet and dry seasons, inducing some birds to migrate or wander widely to find food. Indeed, the <a href="Monsoon" webstripperwas="http://en.wikipedia.org/wiki/Monsoon" title="Monsoon">monsoons</a> of <a href="India" webstripperwas="http://en.wikipedia.org/wiki/India" title="India">India</a> are preceded by the arrival of the <a href="Jacobin_Cuckoo" webstripperwas="http://en.wikipedia.org/wiki/Jacobin_Cuckoo" title="Jacobin Cuckoo">Jacobin Cuckoo</a>, the "harbinger of the monsoon". Other examples include the <a href="Woodland_Kingfisher" webstripperwas="http://en.wikipedia.org/wiki/Woodland_Kingfisher" title="Woodland Kingfisher">Woodland Kingfisher</a> of west <a href="Africa" webstripperwas="http://en.wikipedia.org/wiki/Africa" title="Africa">Africa</a> and many Australian birds.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>There are a few species, notably <a href="Cuckoo" webstripperwas="http://en.wikipedia.org/wiki/Cuckoo" title="Cuckoo">cuckoos</a>, which are genuine long-distance migrants within the tropics. An example is the <a href="Lesser_Cuckoo" webstripperwas="http://en.wikipedia.org/wiki/Lesser_Cuckoo" title="Lesser Cuckoo">Lesser Cuckoo</a>, which breeds in India and spends the non-breeding season in Africa. Such examples help make the case that food supplies, not weather per se, drive migration patterns.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Altitudinal migration is common on mountains worldwide, such as in the <a href="Himalayas" webstripperwas="http://en.wikipedia.org/wiki/Himalayas" title="Himalayas">Himalayas</a> and the <a href="Andes" webstripperwas="http://en.wikipedia.org/wiki/Andes" title="Andes">Andes</a>.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span>[</span>33<span>]</span></a></sup> Quite often, altitudinal migration is combined with distance migration; for example, the Himalayan <a href="Kashmir_Flycatcher" webstripperwas="http://en.wikipedia.org/wiki/Kashmir_Flycatcher" title="Kashmir Flycatcher">Kashmir Flycatcher</a> and <a href="Pied_Thrush" webstripperwas="http://en.wikipedia.org/wiki/Pied_Thrush" title="Pied Thrush">Pied Thrush</a> both move as far south as the highlands of <a href="Sri_Lanka" webstripperwas="http://en.wikipedia.org/wiki/Sri_Lanka" title="Sri Lanka">Sri Lanka</a>. Altitudinal migration may even be important to birds living on relatively small islands, such as the Hawaiian Islands, which have high mountains.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=6" title="Edit section: Irruptions and dispersal">edit</a>]</span> <span class="mw-headline" id="Irruptions_and_dispersal">Irruptions and dispersal</span></h2>
<p>Sometimes circumstances such as a good breeding season followed by a food source failure the following year lead to irruptions in which large numbers of a species move far beyond the normal range. <a href="Bohemian_Waxwing" webstripperwas="http://en.wikipedia.org/wiki/Bohemian_Waxwing" title="Bohemian Waxwing">Bohemian Waxwings</a> well show this unpredictable variation in annual numbers, with five major arrivals in Britain during the nineteenth century, but 18 between the years 1937 and 2000.<sup id="cite_ref-CockerWaxwing_32-1" class="reference"><a href="#cite_note-CockerWaxwing-32"><span>[</span>32<span>]</span></a></sup> <a href="Red_Crossbill" webstripperwas="http://en.wikipedia.org/wiki/Red_Crossbill" title="Red Crossbill">Red Crossbills</a> too are irruptive, with invasions noted in 1251, 1593, 1757, and 1791.<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span>[</span>34<span>]</span></a></sup></p>
<p>The temperate zones of the southern continents have extensive arid areas, particularly in Australia and western southern Africa, and weather-driven movements are common but not always predictable. A couple of weeks of heavy rain in one part or another of the usually dry centre of Australia, for example, causes dramatic plant and invertebrate growth, attracting birds from all directions. This can happen at any time of year, and, in any given area, may not happen again for a decade or more, depending on the frequency of <a href="El_Ni$C3$B1o" webstripperwas="http://en.wikipedia.org/wiki/El_Ni%C3%B1o" title="El Niño" class="mw-redirect">El Niño</a> and <a href="La_Ni$C3$B1a" webstripperwas="http://en.wikipedia.org/wiki/La_Ni%C3%B1a" title="La Niña">La Niña</a> periods.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
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<a href="Rainbow_Bee-eater" webstripperwas="http://en.wikipedia.org/wiki/Rainbow_Bee-eater" title="Rainbow Bee-eater">Rainbow Bee-eater</a></div>
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<p>Bird migration is primarily, but not entirely, a Northern Hemisphere phenomenon. In the Southern Hemisphere, seasonal migration tends to be much less obvious. There are several reasons for this.</p>
<p>First, the largely uninterrupted expanses of land mass or ocean tend not to funnel migrations into narrow and obvious pathways, making them less obvious to the human observer. Second, at least for terrestrial birds, climatic regions tend to fade into one another over a long distance rather than be entirely separate: this means that rather than make long trips over unsuitable habitat to reach particular destinations, migrant species can usually travel at a relaxed pace, feeding as they go. Short of banding studies it is often not obvious that the birds seen in any particular locality as the seasons change are in fact different members of the same species passing through, gradually working their way north or south.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Many species do in fact breed in the temperate southern hemisphere regions and winter further north in the tropics. The southern <a href="Africa" webstripperwas="http://en.wikipedia.org/wiki/Africa" title="Africa">African</a> <a href="Greater_Striped_Swallow" webstripperwas="http://en.wikipedia.org/wiki/Greater_Striped_Swallow" title="Greater Striped Swallow">Greater Striped Swallow</a>, and the <a href="Australia" webstripperwas="http://en.wikipedia.org/wiki/Australia" title="Australia">Australian</a> <a href="Satin_Flycatcher" webstripperwas="http://en.wikipedia.org/wiki/Satin_Flycatcher" title="Satin Flycatcher">Satin Flycatcher</a>, <a href="Dollarbird" webstripperwas="http://en.wikipedia.org/wiki/Dollarbird" title="Dollarbird">Dollarbird</a>, and <a href="Rainbow_Bee-eater" webstripperwas="http://en.wikipedia.org/wiki/Rainbow_Bee-eater" title="Rainbow Bee-eater">Rainbow Bee-eater</a> for example, winters well north of their breeding range.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=7" title="Edit section: Physiology and control">edit</a>]</span> <span class="mw-headline" id="Physiology_and_control">Physiology and control</span></h2>
<p>The control of migration, its timing and response are genetically controlled and appear to be a primitive trait that is present even in non-migratory species of birds. The ability to navigate and orient themselves during migration is a much more complex phenomenon that may include both endogenous programs as well as learning.<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span>[</span>35<span>]</span></a></sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=8" title="Edit section: Timing">edit</a>]</span> <span class="mw-headline" id="Timing">Timing</span></h3>
<p>The primary physiological cue for migration are the changes in the day length. These changes are also related to hormonal changes in the birds.</p>
<p>In the period before migration, many birds display higher activity or <a href="Zugunruhe" webstripperwas="http://en.wikipedia.org/wiki/Zugunruhe" title="Zugunruhe">Zugunruhe</a> (<a href="German_language" webstripperwas="http://en.wikipedia.org/wiki/German_language" title="German language">German</a>: <span lang="de" xml:lang="de"><i>migratory restlessness</i></span>) as well as physiological changes such as increased fat deposition. The occurrence of Zugunruhe even in cage-raised birds with no environmental cues (e.g. shortening of day and falling temperature) has pointed to the role of circannual <a href="Endogenous" webstripperwas="http://en.wikipedia.org/wiki/Endogenous" title="Endogenous" class="mw-redirect">endogenous</a> programs in controlling bird migrations. Caged birds display a preferential flight direction that corresponds with the migratory direction they would take in nature, even changing their preferential direction at roughly the same time their wild conspecifics change course.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>In species where there is polygyny and with considerable sexual dimorphism, there is a tendency for males to return earlier to the breeding sites than their females. This is termed as protandry.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span>[</span>36<span>]</span></a></sup><sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span>[</span>37<span>]</span></a></sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=9" title="Edit section: Orientation and navigation">edit</a>]</span> <span class="mw-headline" id="Orientation_and_navigation">Orientation and navigation</span></h3>
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<div class="thumbinner" style="width:302px;"><a href="File3ABar-tailed_Godwit_migration.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Bar-tailed_Godwit_migration.jpg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Bar-tailed_Godwit_migration.jpg/300px-Bar-tailed_Godwit_migration.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Bar-tailed_Godwit_migration.jpg/300px-Bar-tailed_Godwit_migration.jpg" width="300" height="294" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/f/fe/Bar-tailed_Godwit_migration.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/f/fe/Bar-tailed_Godwit_migration.jpg 2x" /></a>
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The routes of satellite tagged <a href="Bar-tailed_Godwit" webstripperwas="http://en.wikipedia.org/wiki/Bar-tailed_Godwit" title="Bar-tailed Godwit">Bar-tailed Godwits</a> migrating north from <a href="New_Zealand" webstripperwas="http://en.wikipedia.org/wiki/New_Zealand" title="New Zealand">New Zealand</a>. This species has the longest known non-stop migration of any species, up to 10,200 km (6,300 mi).</div>
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<div class="rellink relarticle mainarticle">Main article: <a href="Animal_navigation" webstripperwas="http://en.wikipedia.org/wiki/Animal_navigation" title="Animal navigation">Animal navigation</a></div>
<p><a href="Animal_navigation" webstripperwas="http://en.wikipedia.org/wiki/Animal_navigation" title="Animal navigation">Navigation</a> is based on a variety of senses. Many birds have been shown to use a sun compass. Using the sun for direction involves the need for making compensation based on the time. Navigation has also been shown to be based on a combination of other abilities including the ability to detect magnetic fields (<a href="Magnetoception" webstripperwas="http://en.wikipedia.org/wiki/Magnetoception" title="Magnetoception">magnetoception</a>), use visual landmarks as well as <a href="Olfactory_navigation" webstripperwas="http://en.wikipedia.org/wiki/Olfactory_navigation" title="Olfactory navigation">olfactory cues</a>.<sup id="cite_ref-walraffpigeon_38-0" class="reference"><a href="#cite_note-walraffpigeon-38"><span>[</span>38<span>]</span></a></sup></p>
<p>Long distance migrants are believed to disperse as young birds and form attachments to potential breeding sites and to favourite wintering sites. Once the site attachment is made they show high site-fidelity, visiting the same wintering sites year after year.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span>[</span>39<span>]</span></a></sup></p>
<p>The ability of birds to navigate during migrations cannot be fully explained by endogenous programming, even with the help of responses to environmental cues. The ability to successfully perform long-distance migrations can probably only be fully explained with an accounting for the cognitive ability of the birds to recognize habitats and form mental maps. <a href="Satellite_tracking_(animal_migration)" webstripperwas="http://en.wikipedia.org/wiki/Satellite_tracking_(animal_migration)" title="Satellite tracking (animal migration)" class="mw-redirect">Satellite tracking</a> of day migrating raptors such as Ospreys and Honey Buzzards has shown that older individuals are better at making corrections for wind drift.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span>[</span>40<span>]</span></a></sup></p>
<p>As the circannual patterns indicate, there is a strong <a href="Gene" webstripperwas="http://en.wikipedia.org/wiki/Gene" title="Gene">genetic</a> component to migration in terms of timing and route, but this may be modified by environmental influences. An interesting example where a change of migration route has occurred because of such a geographical barrier is the trend for some <a href="Blackcap" webstripperwas="http://en.wikipedia.org/wiki/Blackcap" title="Blackcap" class="mw-redirect">Blackcaps</a> in central Europe to migrate west and winter in <a href="Great_Britain" webstripperwas="http://en.wikipedia.org/wiki/Great_Britain" title="Great Britain">Britain</a> rather than cross the <a href="Alps" webstripperwas="http://en.wikipedia.org/wiki/Alps" title="Alps">Alps</a>.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Migratory birds may use two <a href="Electromagnetism" webstripperwas="http://en.wikipedia.org/wiki/Electromagnetism" title="Electromagnetism">electromagnetic</a> tools to find their destinations: one that is entirely innate and another that relies on experience. A young bird on its first migration flies in the correct direction according to the Earth's <a href="Magnetic_field" webstripperwas="http://en.wikipedia.org/wiki/Magnetic_field" title="Magnetic field">magnetic field</a>, but does not know how far the journey will be. It does this through a <a href="Radical_pair_mechanism" webstripperwas="http://en.wikipedia.org/wiki/Radical_pair_mechanism" title="Radical pair mechanism" class="mw-redirect">radical pair mechanism</a> whereby chemical reactions in special <a href="Biological_pigment" webstripperwas="http://en.wikipedia.org/wiki/Biological_pigment" title="Biological pigment">photo pigments</a> sensitive to <a href="Color" webstripperwas="http://en.wikipedia.org/wiki/Color" title="Color">long wavelengths</a> are affected by the field. Although this only works during daylight hours, it does not use the position of the sun in any way. At this stage the bird is similar to a <a href="Boy_scout" webstripperwas="http://en.wikipedia.org/wiki/Boy_scout" title="Boy scout" class="mw-redirect">boy scout</a> with a compass but no map, until it grows accustomed to the journey and can put its other facilities to use. With experience they learn various landmarks and this "mapping" is done by <a href="Magnetite" webstripperwas="http://en.wikipedia.org/wiki/Magnetite" title="Magnetite">magnetites</a> in the <a href="Trigeminal_system" webstripperwas="http://en.wikipedia.org/wiki/Trigeminal_system" title="Trigeminal system" class="mw-redirect">trigeminal system</a>, which tell the bird how strong the field is. Because birds migrate between northern and southern regions, the magnetic field strengths at different <a href="Latitude" webstripperwas="http://en.wikipedia.org/wiki/Latitude" title="Latitude">latitudes</a> let it interpret the radical pair mechanism more accurately and let it know when it has reached its destination.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span>[</span>41<span>]</span></a></sup> More recent research has found a neural connection between the eye and "Cluster N", the part of the forebrain that is active during migrational orientation, suggesting that birds may actually be able to <i>see</i> the magnetic field of the earth.<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span>[</span>42<span>]</span></a></sup><sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span>[</span>43<span>]</span></a></sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=10" title="Edit section: Vagrancy">edit</a>]</span> <span class="mw-headline" id="Vagrancy">Vagrancy</span></h3>
<p>Migrating birds can lose their way and appear outside their normal ranges. This can be due to flying past their destinations as in the "spring overshoot"<span id="overshoot"></span> in which birds returning to their breeding areas overshoot and end up further north than intended. <a href="Reverse_migration_(bird_migration)" webstripperwas="http://en.wikipedia.org/wiki/Reverse_migration_(bird_migration)" title="Reverse migration (bird migration)" class="mw-redirect">Reverse migration</a>, where the genetic programming of young birds fails to work properly, can lead to great rarities turning up as vagrants thousands of kilometres out of range. Certain areas, because of their location, have become famous as watchpoints for migrating birds. Examples are the <a href="Point_Pelee_National_Park" webstripperwas="http://en.wikipedia.org/wiki/Point_Pelee_National_Park" title="Point Pelee National Park">Point Pelee National Park</a> in Canada, and <a href="Spurn" webstripperwas="http://en.wikipedia.org/wiki/Spurn" title="Spurn">Spurn</a> in <a href="England" webstripperwas="http://en.wikipedia.org/wiki/England" title="England">England</a>. <a href="Drift_migration" webstripperwas="http://en.wikipedia.org/wiki/Drift_migration" title="Drift migration">Drift migration</a> of birds blown off course by the wind can result in "falls" of large numbers of migrants at coastal sites.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>A related phenomenon called "abmigration" involves birds from one region joining similar birds from a different breeding region in the common winter grounds and then migrating back along with the new population. This is especially common in some waterfowl, which shift from one flyway to another.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span>[</span>44<span>]</span></a></sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=11" title="Edit section: Migration conditioning">edit</a>]</span> <span class="mw-headline" id="Migration_conditioning">Migration conditioning</span></h3>
<p>It has been possible to teach a migration route to a flock of birds, for example in re-introduction schemes. After a trial with <a href="Canada_Goose" webstripperwas="http://en.wikipedia.org/wiki/Canada_Goose" title="Canada Goose">Canada Geese</a>, <a href="Microlight" webstripperwas="http://en.wikipedia.org/wiki/Microlight" title="Microlight" class="mw-redirect">microlight</a> aircraft were used in the US to teach safe migration routes to reintroduced <a href="Whooping_Crane" webstripperwas="http://en.wikipedia.org/wiki/Whooping_Crane" title="Whooping Crane">Whooping Cranes</a>.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span>[</span>45<span>]</span></a></sup><sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span>[</span>46<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=12" title="Edit section: Adaptations">edit</a>]</span> <span class="mw-headline" id="Adaptations">Adaptations</span></h2>
<p>Birds need to alter their metabolism in order to meet the demands of migration. The storage of energy through the accumulation of fat and the control of sleep in nocturnal migrants require special physiological adaptations. In addition, the feathers of a bird suffer from wear-and-tear and require to be molted. The timing of this molt - usually once a year but sometimes two - varies with some species molting prior to moving to their winter grounds and others molting prior to returning to their breeding grounds.<sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span>[</span>47<span>]</span></a></sup><sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span>[</span>48<span>]</span></a></sup> Apart from physiological adaptations, migration sometimes requires behavioural changes such as flying in flocks to reduce the energy used in migration or the risk of predation.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span>[</span>49<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=13" title="Edit section: Evolutionary and ecological factors">edit</a>]</span> <span class="mw-headline" id="Evolutionary_and_ecological_factors">Evolutionary and ecological factors</span></h2>
<p>Migration in birds is highly labile and is believed to have developed independently in many avian lineages.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span>[</span>50<span>]</span></a></sup> While it is agreed that the behavioral and physiological adaptations necessary for migration are under genetic control, some authors have argued that no genetic change is necessary for migratory behavior to develop in a sedentary species because the genetic framework for migratory behavior exists in nearly all avian lineages.<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span>[</span>51<span>]</span></a></sup> This explains the rapid appearance of migratory behavior after the most recent glacial maximum.<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span>[</span>52<span>]</span></a></sup></p>
<p>Whether a particular species migrates depends on a number of factors. The climate of the breeding area is important, and few species can cope with the harsh winters of inland <a href="Canada" webstripperwas="http://en.wikipedia.org/wiki/Canada" title="Canada">Canada</a> or northern <a href="Eurasia" webstripperwas="http://en.wikipedia.org/wiki/Eurasia" title="Eurasia">Eurasia</a>. Thus the partially migratory <a href="Common_Blackbird" webstripperwas="http://en.wikipedia.org/wiki/Common_Blackbird" title="Common Blackbird">Blackbird</a> <i>Turdus merula</i> is migratory in <a href="Scandinavia" webstripperwas="http://en.wikipedia.org/wiki/Scandinavia" title="Scandinavia">Scandinavia</a>, but not in the milder climate of southern Europe. The nature of the staple food is also significant. Most specialist insect eaters outside the tropics are long-distance migrants, and have little choice but to head south in winter.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Sometimes the factors are finely balanced. The <a href="Whinchat" webstripperwas="http://en.wikipedia.org/wiki/Whinchat" title="Whinchat">Whinchat</a> <i>Saxicola rubetra</i> of Europe and the <a href="Siberian_Stonechat" webstripperwas="http://en.wikipedia.org/wiki/Siberian_Stonechat" title="Siberian Stonechat">Siberian Stonechat</a> <i>Saxicola maura</i> of Asia are long-distance migrants wintering in the tropics, whereas their close relative, the <a href="European_Stonechat" webstripperwas="http://en.wikipedia.org/wiki/European_Stonechat" title="European Stonechat">European Stonechat</a> <i>Saxicola rubicola</i> is a <a href="Resident_bird" webstripperwas="http://en.wikipedia.org/wiki/Resident_bird" title="Resident bird" class="mw-redirect">resident bird</a> in most of its range, and moves only short distances from the colder north and east. A possible factor here is that the resident species can often raise an extra brood.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Recent research suggests that long-distance passerine migrants are of <a href="South_America" webstripperwas="http://en.wikipedia.org/wiki/South_America" title="South America">South American</a> and <a href="Africa" webstripperwas="http://en.wikipedia.org/wiki/Africa" title="Africa">African</a>, rather than <a href="Northern_hemisphere" webstripperwas="http://en.wikipedia.org/wiki/Northern_hemisphere" title="Northern hemisphere" class="mw-redirect">northern hemisphere</a>, <a href="Evolution" webstripperwas="http://en.wikipedia.org/wiki/Evolution" title="Evolution">evolutionary</a> origins. They are effectively southern species coming north to breed rather than northern species going south to winter.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Theoretical analyses, summarized by Alerstam (2001), show that detours that increase flight distance by up to 20% will often be adaptive on <a href="Aerodynamics" webstripperwas="http://en.wikipedia.org/wiki/Aerodynamics" title="Aerodynamics">aerodynamic</a> grounds - a bird that loads itself with food to cross a long barrier flies less efficiently. However some species show circuitous migratory routes that reflect historical range expansions and are far from optimal in ecological terms. An example is the migration of continental populations of <a href="Swainson$27s_Thrush" webstripperwas="http://en.wikipedia.org/wiki/Swainson%27s_Thrush" title="Swainson's Thrush">Swainson's Thrush</a>, which fly far east across <a href="North_America" webstripperwas="http://en.wikipedia.org/wiki/North_America" title="North America">North America</a> before turning south via <a href="Florida.html" webstripperwas="/wiki/Florida" title="Florida">Florida</a> to reach northern <a href="South_America" webstripperwas="http://en.wikipedia.org/wiki/South_America" title="South America">South America</a>; this route is believed to be the consequence of a range expansion that occurred about 10,000 years ago. Detours may also be caused by differential wind conditions, predation risk, or other factors.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=14" title="Edit section: Climate change">edit</a>]</span> <span class="mw-headline" id="Climate_change">Climate change</span></h3>
<p>Large scale climatic changes, as have been experienced in the past, are expected to have an effect on the timing of migration. Studies have shown a variety of effects including timing changes in migration, breeding<sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span>[</span>53<span>]</span></a></sup> as well as population variations.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span>[</span>54<span>]</span></a></sup><sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span>[</span>55<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=15" title="Edit section: Ecological effects">edit</a>]</span> <span class="mw-headline" id="Ecological_effects">Ecological effects</span></h2>
<p>The migration of birds also aids the movement of other species, including those of <a href="Ectoparasite" webstripperwas="http://en.wikipedia.org/wiki/Ectoparasite" title="Ectoparasite" class="mw-redirect">ectoparasites</a> such as ticks and lice,<sup id="cite_ref-56" class="reference"><a href="#cite_note-56"><span>[</span>56<span>]</span></a></sup> which in turn may carry micro-organisms including those of concern to human health. Considerable interest has been taken due to the global spread of <a href="Avian_influenza" webstripperwas="http://en.wikipedia.org/wiki/Avian_influenza" title="Avian influenza">avian influenza</a>, however migrant birds have not been found to be a special risk, with import of pet and domestic birds being a greater threat.<sup id="cite_ref-57" class="reference"><a href="#cite_note-57"><span>[</span>57<span>]</span></a></sup> Some viruses that are maintained in birds without lethal effects, such as the <a href="West_Nile_virus" webstripperwas="http://en.wikipedia.org/wiki/West_Nile_Virus" title="West Nile Virus" class="mw-redirect">West Nile Virus</a> may however be spread by migrating birds.<sup id="cite_ref-58" class="reference"><a href="#cite_note-58"><span>[</span>58<span>]</span></a></sup> Birds may also have a role in the dispersal of propagules of plants and plankton.<sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span>[</span>59<span>]</span></a></sup><sup id="cite_ref-60" class="reference"><a href="#cite_note-60"><span>[</span>60<span>]</span></a></sup></p>
<p>Some predators take advantage of the concentration of birds during migration. <a href="Greater_Noctule_bat" webstripperwas="http://en.wikipedia.org/wiki/Greater_Noctule_bat" title="Greater Noctule bat" class="mw-redirect">Greater Noctule bats</a> feed on nocturnal migrating passerines.<sup id="cite_ref-bats_4-1" class="reference"><a href="#cite_note-bats-4"><span>[</span>4<span>]</span></a></sup> Some birds of prey specialize on migrating waders.<sup id="cite_ref-61" class="reference"><a href="#cite_note-61"><span>[</span>61<span>]</span></a></sup></p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=16" title="Edit section: Study techniques">edit</a>]</span> <span class="mw-headline" id="Study_techniques">Study techniques</span></h2>
<p>Early studies on the timing of migration began in 1749 in Finland, with Johannes Leche of Turku collecting the dates of arrivals of spring migrants.<sup id="cite_ref-62" class="reference"><a href="#cite_note-62"><span>[</span>62<span>]</span></a></sup></p>
<p>Bird migration routes have been studied by a variety of techniques including the oldest, marking. Swans have been marked with a nick on the beak since about 1560 in England. Scientific <a href="Bird_ringing" webstripperwas="http://en.wikipedia.org/wiki/Bird_ringing" title="Bird ringing">ringing</a> was pioneered by <a href="Hans_Christian_Cornelius_Mortensen" webstripperwas="http://en.wikipedia.org/wiki/Hans_Christian_Cornelius_Mortensen" title="Hans Christian Cornelius Mortensen">Mortensen</a> in 1899.<sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span>[</span>63<span>]</span></a></sup> Other techniques include <a href="Radar" webstripperwas="http://en.wikipedia.org/wiki/Radar" title="Radar">radar</a> and <a href="GPS_satellite" webstripperwas="http://en.wikipedia.org/wiki/GPS_satellite" title="GPS satellite" class="mw-redirect">satellite tracking</a>.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Stable isotopes of hydrogen, oxygen, carbon, nitrogen, and sulphur can establish avian migratory connectivity between wintering sites and breeding grounds. Stable isotopic methods to establish migratory linkage rely on spatial isotopic differences in bird diet that are incorporated into inert tissues like feathers, or into growing tissues such as claws and muscle or blood.<sup id="cite_ref-64" class="reference"><a href="#cite_note-64"><span>[</span>64<span>]</span></a></sup><sup id="cite_ref-65" class="reference"><a href="#cite_note-65"><span>[</span>65<span>]</span></a></sup></p>
<p>An approach to identify migration intensity makes use of upward pointing microphones to record the nocturnal contact calls of flocks flying overhead. These are then analyzed in a laboratory to measure time, frequency and species.<sup id="cite_ref-66" class="reference"><a href="#cite_note-66"><span>[</span>66<span>]</span></a></sup></p>
<div class="thumb tright">
<div class="thumbinner" style="width:222px;"><a href="File3AEmlenFunnel.svg" webstripperwas="http://en.wikipedia.org/wiki/File:EmlenFunnel.svg" class="image"><img alt="" src="upload.wikimedia.org/wikipedia/commons/thumb/4/44/EmlenFunnel.svg/220px-EmlenFunnel.svg.png" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/EmlenFunnel.svg/220px-EmlenFunnel.svg.png" width="220" height="109" class="thumbimage" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/44/EmlenFunnel.svg/330px-EmlenFunnel.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/44/EmlenFunnel.svg/440px-EmlenFunnel.svg.png 2x" /></a>
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<a href="Emlen_funnel" webstripperwas="http://en.wikipedia.org/wiki/Emlen_funnel" title="Emlen funnel">Emlen funnel</a></div>
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<p>An older technique to quantify migration involves observing the face of the moon towards full moon and counting the silhouettes of flocks of birds as they fly at night.<sup id="cite_ref-67" class="reference"><a href="#cite_note-67"><span>[</span>67<span>]</span></a></sup><sup id="cite_ref-68" class="reference"><a href="#cite_note-68"><span>[</span>68<span>]</span></a></sup></p>
<p>Orientation behaviour studies have been traditionally carried out using variants of a setup known as the <b>Emlen funnel</b>, which consists of a circular cage with the top covered by glass or wire-screen so that either the sky is visible or the setup is placed in a planetarium or with other controls on environmental cues. The orientation behaviour of the bird inside the cage is studied quantitatively using the distribution of marks that the bird leaves on the walls of the cage.<sup id="cite_ref-69" class="reference"><a href="#cite_note-69"><span>[</span>69<span>]</span></a></sup> Other approaches used in pigeon homing studies make use of the direction in which the bird vanishes on the horizon.</p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=17" title="Edit section: Threats and conservation">edit</a>]</span> <span class="mw-headline" id="Threats_and_conservation">Threats and conservation</span></h2>
<p>Human activities have threatened many migratory bird species. The distances involved in bird migration mean that they often cross political boundaries of countries and conservation measures require international cooperation. Several international treaties have been signed to protect migratory species including the <a href="Migratory_Bird_Treaty_Act" webstripperwas="http://en.wikipedia.org/wiki/Migratory_Bird_Treaty_Act" title="Migratory Bird Treaty Act" class="mw-redirect">Migratory Bird Treaty Act</a> of 1918 of the US.<sup id="cite_ref-70" class="reference"><a href="#cite_note-70"><span>[</span>70<span>]</span></a></sup> and the <a href="African-Eurasian_Migratory_Waterbird_Agreement" webstripperwas="http://en.wikipedia.org/wiki/African-Eurasian_Migratory_Waterbird_Agreement" title="African-Eurasian Migratory Waterbird Agreement" class="mw-redirect">African-Eurasian Migratory Waterbird Agreement</a><sup id="cite_ref-71" class="reference"><a href="#cite_note-71"><span>[</span>71<span>]</span></a></sup></p>
<p>The concentration of birds during migration can put species at risk. Some spectacular migrants have already gone extinct, the most notable being the <a href="Passenger_Pigeon" webstripperwas="http://en.wikipedia.org/wiki/Passenger_Pigeon" title="Passenger Pigeon">Passenger Pigeon</a> (<i>Ectopistes migratorius</i>). During migration the flocks were a mile (1.6 km) wide and 300 miles (480 km) long, taking several days to pass and containing up to a billion birds.<sup class="Template-Fact" style="white-space:nowrap;">[<i><a href="Wikipedia3ACitation_needed.html" webstripperwas="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup></p>
<p>Other significant areas include stop-over sites between the wintering and breeding territories.<sup id="cite_ref-72" class="reference"><a href="#cite_note-72"><span>[</span>72<span>]</span></a></sup> A capture-recapture study of passerine migrants with high fidelity for breeding and wintering sites did not show similar strict association with stop-over sites.<sup id="cite_ref-73" class="reference"><a href="#cite_note-73"><span>[</span>73<span>]</span></a></sup></p>
<p><a href="Hunting" webstripperwas="http://en.wikipedia.org/wiki/Hunting" title="Hunting">Hunting</a> along the migratory route can also take a heavy toll. The populations of <a href="Siberian_Crane" webstripperwas="http://en.wikipedia.org/wiki/Siberian_Crane" title="Siberian Crane">Siberian Cranes</a> that wintered in <a href="India" webstripperwas="http://en.wikipedia.org/wiki/India" title="India">India</a> declined due to hunting along the route, particularly in <a href="Afghanistan" webstripperwas="http://en.wikipedia.org/wiki/Afghanistan" title="Afghanistan">Afghanistan</a> and <a href="Central_Asia" webstripperwas="http://en.wikipedia.org/wiki/Central_Asia" title="Central Asia">Central Asia</a>. Birds were last seen in their favourite wintering grounds in <a href="Keoladeo_National_Park" webstripperwas="http://en.wikipedia.org/wiki/Keoladeo_National_Park" title="Keoladeo National Park">Keoladeo National Park</a> in 2002.<sup id="cite_ref-74" class="reference"><a href="#cite_note-74"><span>[</span>74<span>]</span></a></sup></p>
<p>Structures such as power lines, wind farms and offshore oil-rigs have also been known to affect migratory birds.<sup id="cite_ref-75" class="reference"><a href="#cite_note-75"><span>[</span>75<span>]</span></a></sup> Habitat destruction by land use changes is the biggest threat, and shallow wetlands that are stopover and wintering sites for migratory birds are particularly threatened by draining and reclamation for human use.</p>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=18" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span></h2>
<ul>
<li><a href="Winged_Migration" webstripperwas="http://en.wikipedia.org/wiki/Winged_Migration" title="Winged Migration">Winged Migration</a>, 2001 documentary film</li>
<li><a href="Isoscapes" webstripperwas="http://en.wikipedia.org/wiki/Isoscapes" title="Isoscapes">Isoscapes</a></li>
<li><a href="Smithsonian_Migratory_Bird_Center" webstripperwas="http://en.wikipedia.org/wiki/Smithsonian_Migratory_Bird_Center" title="Smithsonian Migratory Bird Center">Smithsonian Migratory Bird Center</a></li>
</ul>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=19" title="Edit section: References">edit</a>]</span> <span class="mw-headline" id="References">References</span></h2>
<div class="reflist references-column-count references-column-count-2" style="-moz-column-count: 2; -webkit-column-count: 2; column-count: 2; list-style-type: decimal;">
<ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><span class="citation book">Peter Berthold, Hans-Günther Bauer, Valerie Westhead (2001). <i>Bird Migration: A General Survey</i>. Oxford: <a href="Oxford_University_Press" webstripperwas="http://en.wikipedia.org/wiki/Oxford_University_Press" title="Oxford University Press">Oxford University Press</a>. <a href="International_Standard_Book_Number.html" webstripperwas="/wiki/International_Standard_Book_Number" title="International Standard Book Number">ISBN</a> <a href="Special3ABookSources/0-19-850787-9" webstripperwas="http://en.wikipedia.org/wiki/Special:BookSources/0-19-850787-9" title="Special:BookSources/0-19-850787-9">0-19-850787-9</a>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Peter+Berthold%2C+Hans-G%C3%BCnther+Bauer%2C+Valerie+Westhead&rft.pub=Oxford+University+Press&rft.place=Oxford&rft.btitle=Bird+Migration%3A+A+General+Survey&rft.isbn=0-19-850787-9&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.date=2001&rft.au=Peter+Berthold%2C+Hans-G%C3%BCnther+Bauer%2C+Valerie+Westhead&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><span class="citation journal">Sekercioglu, C.H. (2007). "Conservation ecology: area trumps mobility in fragment bird extinctions". <i>Current Biology</i> <b>17</b> (8): 283–286.</span><span title="ctx_ver=Z39.88-2004&rft.volume=17&rft.atitle=Conservation+ecology%3A+area+trumps+mobility+in+fragment+bird+extinctions&rft.genre=book&rft.aulast=Sekercioglu%2C+C.H.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2007&rft.pages=283%E2%80%93286&rft.jtitle=Current+Biology&rft.issue=8&rft.btitle=Conservation+ecology%3A+area+trumps+mobility+in+fragment+bird+extinctions&rft.au=Sekercioglu%2C+C.H.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><span class="citation journal">Dondini, G., Vergari, S. (2000). "Carnivory in the greater noctule bat (<i>Nyctalus lasiopterus</i>) in Italy". <i>Journal of Zoology</i> <b>251</b> (2): 233–236. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1111%2Fj.1469-7998.2000.tb00606.x" >10.1111/j.1469-7998.2000.tb00606.x</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=251&rft.atitle=Carnivory+in+the+greater+noctule+bat+%28%27%27Nyctalus+lasiopterus%27%27%29+in+Italy&rft.genre=book&rft.aulast=Dondini%2C+G.%2C+Vergari%2C+S.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2000&rft.pages=233%E2%80%93236&rft.jtitle=Journal+of+Zoology&rft.issue=2&rft.btitle=Carnivory+in+the+greater+noctule+bat+%28%27%27Nyctalus+lasiopterus%27%27%29+in+Italy&rft.au=Dondini%2C+G.%2C+Vergari%2C+S.&rft_id=info%3Adoi%2F10.1111%2Fj.1469-7998.2000.tb00606.x&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-bats-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-bats_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-bats_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><span class="citation journal">Popa-Lisseanu, A. G., Delgado-Huertas, A., Forero, M. G., Rodriguez, A., Arlettaz, R. & Ibanez, C. (2007). <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1784064" >"Bats' Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds"</a>. In Rands, Sean. <i>PLoS ONE</i> <b>2</b> (2): e205. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1371%2Fjournal.pone.0000205" >10.1371/journal.pone.0000205</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1784064" >1784064</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/17299585" >17299585</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=2&rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1784064&rft.atitle=Bats%27+Conquest+of+a+Formidable+Foraging+Niche%3A+The+Myriads+of+Nocturnally+Migrating+Songbirds&rft.genre=book&rft.aulast=Popa-Lisseanu%2C+A.+G.%2C+Delgado-Huertas%2C+A.%2C+Forero%2C+M.+G.%2C+Rodriguez%2C+A.%2C+Arlettaz%2C+R.+%26+Ibanez%2C+C.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2007&rft.pages=e205&rft.jtitle=PLoS+ONE&rft.issue=2&rft.btitle=Bats%27+Conquest+of+a+Formidable+Foraging+Niche%3A+The+Myriads+of+Nocturnally+Migrating+Songbirds&rft.au=Popa-Lisseanu%2C+A.+G.%2C+Delgado-Huertas%2C+A.%2C+Forero%2C+M.+G.%2C+Rodriguez%2C+A.%2C+Arlettaz%2C+R.+%26+Ibanez%2C+C.&rft_id=info%3Adoi%2F10.1371%2Fjournal.pone.0000205&rft_id=info%3Apmid%2F17299585&rft_id=info%3Apmc%2F1784064&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><span class="citation journal">Ibáñez, C., Juste, J., García-Mudarra, J. L., Agirre-Mendi, P. T. (2001). <a rel="nofollow" class="external text" href="http://www.pnas.org/cgi/content/full/98/17/9700" >"Bat predation on nocturnally migrating birds"</a>. <i>PNAS</i> <b>98</b> (17): 9700–9702. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1073%2Fpnas.171140598" >10.1073/pnas.171140598</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC55515" >55515</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/11493689" >11493689</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=98&rft_id=http%3A%2F%2Fwww.pnas.org%2Fcgi%2Fcontent%2Ffull%2F98%2F17%2F9700%23B8&rft.atitle=Bat+predation+on+nocturnally+migrating+birds&rft.genre=book&rft.aulast=Ib%C3%A1%C3%B1ez%2C+C.%2C+Juste%2C+J.%2C+Garc%C3%ADa-Mudarra%2C+J.+L.%2C+Agirre-Mendi%2C+P.+T.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2001&rft.pages=9700%E2%80%939702&rft.jtitle=PNAS&rft.issue=17&rft.btitle=Bat+predation+on+nocturnally+migrating+birds&rft.au=Ib%C3%A1%C3%B1ez%2C+C.%2C+Juste%2C+J.%2C+Garc%C3%ADa-Mudarra%2C+J.+L.%2C+Agirre-Mendi%2C+P.+T.&rft_id=info%3Adoi%2F10.1073%2Fpnas.171140598&rft_id=info%3Apmid%2F11493689&rft_id=info%3Apmc%2F55515&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-newton-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-newton_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-newton_6-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-newton_6-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-newton_6-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><span class="citation book">Newton, I. (2008). <i>The Migration Ecology of Birds</i>. Elselvier. <a href="International_Standard_Book_Number.html" webstripperwas="/wiki/International_Standard_Book_Number" title="International Standard Book Number">ISBN</a> <a href="Special3ABookSources/978-0-12-517367-4" webstripperwas="http://en.wikipedia.org/wiki/Special:BookSources/978-0-12-517367-4" title="Special:BookSources/978-0-12-517367-4">978-0-12-517367-4</a>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Newton%2C+I.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.btitle=The+Migration+Ecology+of+Birds.&rft.pub=Elselvier&rft.isbn=978-0-12-517367-4&rft.genre=book&rft.date=2008&rft.au=Newton%2C+I.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><span class="citation journal">Chan K (2001). "Partial migration in Australian landbirds: a review". <i>Emu</i> <b>101</b> (4): 281–292. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1071%2FMU00034" >10.1071/MU00034</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=101&rft.atitle=Partial+migration+in+Australian+landbirds%3A+a+review&rft.genre=book&rft.aulast=Chan+K&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2001&rft.pages=281%E2%80%93292&rft.jtitle=Emu&rft.issue=4&rft.btitle=Partial+migration+in+Australian+landbirds%3A+a+review&rft.au=Chan+K&rft_id=info%3Adoi%2F10.1071%2FMU00034&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><span class="citation journal">Boland, J. M. (1990). <a rel="nofollow" class="external text" href="http://sora.unm.edu/sites/default/files/journals/condor/v092n02/p0284-p0290.pdf" >"Leapfrog migration in North American shorebirds: intra- and interspecific examples"</a> (PDF). <i>The Condor</i> <b>92</b> (2): 284–290. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.2307%2F1368226" >10.2307/1368226</a>. <a href="JSTOR" webstripperwas="http://en.wikipedia.org/wiki/JSTOR" title="JSTOR">JSTOR</a> <a rel="nofollow" class="external text" href="http://www.jstor.org/stable/1368226" >1368226</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=92&rft_id=http%3A%2F%2Fsora.unm.edu%2Fsites%2Fdefault%2Ffiles%2Fjournals%2Fcondor%2Fv092n02%2Fp0284-p0290.pdf&rft.atitle=Leapfrog+migration+in+North+American+shorebirds%3A+intra-+and+interspecific+examples&rft.genre=book&rft.jstor=1368226&rft.aulast=Boland%2C+J.+M.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=1990&rft.pages=284%E2%80%93290&rft.jtitle=The+Condor&rft.issue=2&rft.btitle=Leapfrog+migration+in+North+American+shorebirds%3A+intra-+and+interspecific+examples&rft.au=Boland%2C+J.+M.&rft_id=info%3Adoi%2F10.2307%2F1368226&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><span class="citation journal">Panov, Ilya N (2011). <a rel="nofollow" class="external text" href="http://www.zin.ru/journals/AEB/pdf/Panov_2011_19_AEB.pdf" >"Overlap between moult and autumn migration in passerines in northern taiga zone of Eastern Fennoscandia"</a>. <i>Avian Ecology and Behaviour</i> <b>19</b>: 33–64.</span><span title="ctx_ver=Z39.88-2004&rft.volume=19&rft_id=http%3A%2F%2Fwww.zin.ru%2Fjournals%2FAEB%2Fpdf%2FPanov_2011_19_AEB.pdf&rft.atitle=Overlap+between+moult+and+autumn+migration+in+passerines+in+northern+taiga+zone+of+Eastern+Fennoscandia&rft.genre=book&rft.aulast=Panov%2C+Ilya+N&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Overlap+between+moult+and+autumn+migration+in+passerines+in+northern+taiga+zone+of+Eastern+Fennoscandia&rft.jtitle=Avian+Ecology+and+Behaviour&rft.pages=33%E2%80%9364&rft.date=2011&rft.au=Panov%2C+Ilya+N&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><span class="citation journal">Hummel D., Beukenberg M. (1989). "Aerodynamische Interferenzeffekte beim Formationsfl ug von Vogeln". <i>J. Ornithol</i> <b>130</b>: 15–24. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1007%2FBF01647158" >10.1007/BF01647158</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=130&rft.atitle=Aerodynamische+Interferenzeffekte+beim+Formationsfl+ug+von+Vogeln&rft.genre=book&rft.aulast=Hummel+D.%2C+Beukenberg+M.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Aerodynamische+Interferenzeffekte+beim+Formationsfl+ug+von+Vogeln&rft.jtitle=J.+Ornithol&rft.pages=15%E2%80%9324&rft.date=1989&rft.au=Hummel+D.%2C+Beukenberg+M.&rft_id=info%3Adoi%2F10.1007%2FBF01647158&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><span class="citation journal">Cutts, C. J. & J R Speakman (1994). <a rel="nofollow" class="external text" href="http://jeb.biologists.org/cgi/reprint/189/1/251.pdf" >"Energy savings in formation flight of Pink-footed Geese"</a> (PDF). <i>J. Exp. Biol.</i> <b>189</b> (1): 251–261. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/9317742" >9317742</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=189&rft_id=http%3A%2F%2Fjeb.biologists.org%2Fcgi%2Freprint%2F189%2F1%2F251.pdf&rft.atitle=Energy+savings+in+formation+flight+of+Pink-footed+Geese&rft.genre=book&rft.aulast=Cutts%2C+C.+J.+%26+J+R+Speakman&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=1994&rft.pages=251%E2%80%93261&rft.jtitle=J.+Exp.+Biol.&rft.issue=1&rft.btitle=Energy+savings+in+formation+flight+of+Pink-footed+Geese&rft.au=Cutts%2C+C.+J.+%26+J+R+Speakman&rft_id=info%3Apmid%2F9317742&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><span class="citation journal">Geroudet, P. (1954). "Des oiseaux migrateurs trouvés sur la glacier de Khumbu dans l'Himalaya". <i>Nos Oiseaux</i> <b>22</b>: 254.</span><span title="ctx_ver=Z39.88-2004&rft.volume=22&rft.atitle=Des+oiseaux+migrateurs+trouv%C3%A9s+sur+la+glacier+de+Khumbu+dans+l%27Himalaya&rft.genre=book&rft.aulast=Geroudet%2C+P.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Des+oiseaux+migrateurs+trouv%C3%A9s+sur+la+glacier+de+Khumbu+dans+l%27Himalaya&rft.jtitle=Nos+Oiseaux&rft.pages=254&rft.date=1954&rft.au=Geroudet%2C+P.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><span class="citation journal">Swan, L. W. (1970). "Goose of the Himalayas". <i>Nat. Hist.</i> <b>79</b> (10): 68–75.</span><span title="ctx_ver=Z39.88-2004&rft.volume=79&rft.atitle=Goose+of+the+Himalayas&rft.genre=book&rft.aulast=Swan%2C+L.+W.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=1970&rft.pages=68%E2%80%9375&rft.jtitle=Nat.+Hist.&rft.issue=10&rft.btitle=Goose+of+the+Himalayas&rft.au=Swan%2C+L.+W.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><span class="citation book">Dorst, J. (1963). <i>The migration of birds</i>. Houghton Mifflin Co., Boston. p. 476.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Dorst%2C+J.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.pages=476&rft.btitle=The+migration+of+birds.&rft.pub=Houghton+Mifflin+Co.%2C+Boston.&rft.genre=book&rft.date=1963&rft.au=Dorst%2C+J.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><span class="citation journal">Eastwood, E. & G. C. Rider. (1965). "Some radar measurements of the altitude of bird flight". <i>British Birds</i> <b>58</b>: 393–426.</span><span title="ctx_ver=Z39.88-2004&rft.volume=58&rft.atitle=Some+radar+measurements+of+the+altitude+of+bird+flight&rft.genre=book&rft.aulast=Eastwood%2C+E.+%26+G.+C.+Rider.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Some+radar+measurements+of+the+altitude+of+bird+flight&rft.jtitle=British+Birds&rft.pages=393%E2%80%93426&rft.date=1965&rft.au=Eastwood%2C+E.+%26+G.+C.+Rider.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><span class="citation journal">Williams, G. G. (1950). "Weather and spring migration". <i>Auk</i> <b>67</b>: 52–65.</span><span title="ctx_ver=Z39.88-2004&rft.volume=67&rft.atitle=Weather+and+spring+migration&rft.genre=book&rft.aulast=Williams%2C+G.+G.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Weather+and+spring+migration&rft.jtitle=Auk&rft.pages=52%E2%80%9365&rft.date=1950&rft.au=Williams%2C+G.+G.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-Lincoln-17"><span class="mw-cite-backlink">^ <a href="#cite_ref-Lincoln_17-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Lincoln_17-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Lincoln_17-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><span class="citation book">Lincoln, F. C. (1979). <a rel="nofollow" class="external text" href="http://www.archive.org/details/migrationofbirds00lincrich" ><i>Migration of Birds.</i></a>. <a href="Fish_and_Wildlife_Service" webstripperwas="http://en.wikipedia.org/wiki/Fish_and_Wildlife_Service" title="Fish and Wildlife Service" class="mw-redirect">Fish and Wildlife Service</a>. <i>Circular 16</i>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Lincoln%2C+F.+C.&rft.pub=Fish+and+Wildlife+Service.+%27%27Circular+16%27%27&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=1979&rft_id=http%3A%2F%2Fwww.archive.org%2Fdetails%2Fmigrationofbirds00lincrich&rft.btitle=Migration+of+Birds.&rft.genre=book&rft.au=Lincoln%2C+F.+C.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><span class="citation book">Cocker, Mark; Mabey, Richard (2005). <i>Birds Britannica</i>. Chatto & Windus. p. 315. <a href="International_Standard_Book_Number.html" webstripperwas="/wiki/International_Standard_Book_Number" title="International Standard Book Number">ISBN</a> <a href="Special3ABookSources/0-701-16907-9" webstripperwas="http://en.wikipedia.org/wiki/Special:BookSources/0-701-16907-9" title="Special:BookSources/0-701-16907-9">0-701-16907-9</a>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Cocker%2C+Mark%3B+Mabey%2C+Richard&rft.pub=Chatto+%26+Windus&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.btitle=Birds+Britannica&rft.isbn=0-701-16907-9&rft.pages=315&rft.genre=book&rft.date=2005&rft.au=Cocker%2C+Mark%3B+Mabey%2C+Richard&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-GilbertWhite1-19"><span class="mw-cite-backlink">^ <a href="#cite_ref-GilbertWhite1_19-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-GilbertWhite1_19-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">White, 1898. pp. 27–28</span></li>
<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">White, 1898. pp. 161–162</span></li>
<li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text">Bewick, 1797. p. 300</span></li>
<li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text">Bewick, 1797. pp. 302–303</span></li>
<li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.allaboutbirds.org/guide/Dark-eyed_Junco/id" >Dark-Eyed Junco</a></span></li>
<li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.allaboutbirds.org/guide/American_Goldfinch/id" >American Goldfinch</a></span></li>
<li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><span class="citation journal">Gill, Robert E. Jr., Theunis Piersma, Gary Hufford, Rene Servranckx, Adrian Riegen (2005). "Crossing the ultimate ecological barrier: evidence for an 11,000 km-long nonstop flight from Alaska to New Zealand and Eastern Australia by Bar-tailed Godwits". <i>The Condor</i> <b>107</b> (1): 1–20. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1650%2F7613" >10.1650/7613</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=107&rft.atitle=Crossing+the+ultimate+ecological+barrier%3A+evidence+for+an+11%2C000+km-long+nonstop+flight+from+Alaska+to+New+Zealand+and+Eastern+Australia+by+Bar-tailed+Godwits&rft.genre=book&rft.aulast=Gill%2C+Robert+E.+Jr.%2C+Theunis+Piersma%2C+Gary+Hufford%2C+Rene+Servranckx%2C+Adrian+Riegen&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2005&rft.pages=1%E2%80%9320&rft.jtitle=The+Condor&rft.issue=1&rft.btitle=Crossing+the+ultimate+ecological+barrier%3A+evidence+for+an+11%2C000+km-long+nonstop+flight+from+Alaska+to+New+Zealand+and+Eastern+Australia+by+Bar-tailed+Godwits&rft.au=Gill%2C+Robert+E.+Jr.%2C+Theunis+Piersma%2C+Gary+Hufford%2C+Rene+Servranckx%2C+Adrian+Riegen&rft_id=info%3Adoi%2F10.1650%2F7613&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><span class="citation web">Anon (18 April 2002). <a rel="nofollow" class="external text" href="http://edition.cnn.com/2002/WORLD/europe/04/18/britain.bird/index.html?iref=allsearch" >"Oldest bird clocks 5 million miles"</a>. CNN.com<span class="reference-accessdate">. Retrieved 31 March 2013</span>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Anon&rft.pub=CNN.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=18+April+2002&rft_id=http%3A%2F%2Fedition.cnn.com%2F2002%2FWORLD%2Feurope%2F04%2F18%2Fbritain.bird%2Findex.html%3Firef%3Dallsearch&rft.btitle=Oldest+bird+clocks+5+million+miles&rft.genre=book&rft.au=Anon&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-Gavashelishvili11-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-Gavashelishvili11_27-0">^</a></b></span> <span class="reference-text"><span class="citation journal">Maanen, E. van; Goradze, I.; Gavashelishvili, A.; Goradze, R. (2001). "Opinion: Trapping and hunting of migratory raptors in western Georgia". <i>Bird Conservation International</i> <b>11</b> (2): 77–92. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1017%2FS095927090100017X" >10.1017/S095927090100017X</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=11&rft.atitle=Opinion%3A+Trapping+and+hunting+of+migratory+raptors+in+western+Georgia&rft.genre=book&rft.aulast=Maanen%2C+E.+van%3B+Goradze%2C+I.%3B+Gavashelishvili%2C+A.%3B+Goradze%2C+R.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2001&rft.pages=77%E2%80%9392&rft.jtitle=Bird+Conservation+International&rft.issue=2&rft.btitle=Opinion%3A+Trapping+and+hunting+of+migratory+raptors+in+western+Georgia&rft.au=Maanen%2C+E.+van%3B+Goradze%2C+I.%3B+Gavashelishvili%2C+A.%3B+Goradze%2C+R.&rft_id=info%3Adoi%2F10.1017%2FS095927090100017X&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text">Gensbol, B; (1984) Collins Guide to the Birds of Prey of Britain and Europe, p.28</span></li>
<li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text"><span class="citation journal">Schmaljohann, Heiko, Felix Liechti and Bruno Bruderer (2007). <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2197203" >"Songbird migration across the Sahara: the non-stop hypothesis rejected!"</a>. <i>Proc Biol Sci.</i> <b>274</b> (1610): 735–739. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1098%2Frspb.2006.0011" >10.1098/rspb.2006.0011</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2197203" >2197203</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/17254999" >17254999</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=274&rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2197203&rft.atitle=Songbird+migration+across+the+Sahara%3A+the+non-stop+hypothesis+rejected%21&rft.genre=book&rft.aulast=Schmaljohann%2C+Heiko%2C+Felix+Liechti+and+Bruno+Bruderer&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2007&rft.pages=735%E2%80%93739&rft.jtitle=Proc+Biol+Sci.&rft.issue=1610&rft.btitle=Songbird+migration+across+the+Sahara%3A+the+non-stop+hypothesis+rejected%21&rft.au=Schmaljohann%2C+Heiko%2C+Felix+Liechti+and+Bruno+Bruderer&rft_id=info%3Adoi%2F10.1098%2Frspb.2006.0011&rft_id=info%3Apmid%2F17254999&rft_id=info%3Apmc%2F2197203&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><span class="citation journal">Rattenborg, N.C., Mandt, B.H., Obermeyer, W.H., Winsauer, P.J., Huber, R. (2004). <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC449897" >"Migratory Sleeplessness in the White-Crowned Sparrow (Zonotrichia leucophrys gambelii)"</a>. <i>PLoS Biol.</i> <b>2</b> (7): e212. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1371%2Fjournal.pbio.0020212" >10.1371/journal.pbio.0020212</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC449897" >449897</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/15252455" >15252455</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=2&rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC449897&rft.atitle=Migratory+Sleeplessness+in+the+White-Crowned+Sparrow+%28Zonotrichia+leucophrys+gambelii%29&rft.genre=book&rft.aulast=Rattenborg%2C+N.C.%2C+Mandt%2C+B.H.%2C+Obermeyer%2C+W.H.%2C+Winsauer%2C+P.J.%2C+Huber%2C+R.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2004&rft.pages=e212&rft.jtitle=PLoS+Biol.&rft.issue=7&rft.btitle=Migratory+Sleeplessness+in+the+White-Crowned+Sparrow+%28Zonotrichia+leucophrys+gambelii%29&rft.au=Rattenborg%2C+N.C.%2C+Mandt%2C+B.H.%2C+Obermeyer%2C+W.H.%2C+Winsauer%2C+P.J.%2C+Huber%2C+R.&rft_id=info%3Adoi%2F10.1371%2Fjournal.pbio.0020212&rft_id=info%3Apmid%2F15252455&rft_id=info%3Apmc%2F449897&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text">Cocker, 2005. p. 378</span></li>
<li id="cite_note-CockerWaxwing-32"><span class="mw-cite-backlink">^ <a href="#cite_ref-CockerWaxwing_32-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-CockerWaxwing_32-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Cocker, 2005. p. 326</span></li>
<li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><span class="citation web">Kreft, Stefan (23 June 2004). <a rel="nofollow" class="external text" href="http://www.groms.de/groms/work25/vortrag/KREFT.PDF" >"The Fourth Dimension: An Overview of Altitudinal Migration"</a>. 25th Annual Bonn Convention, Berlin<span class="reference-accessdate">. Retrieved 27 March 2013</span>.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Kreft%2C+Stefan&rft.pub=25th+Annual+Bonn+Convention%2C+Berlin&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=23+June+2004&rft_id=http%3A%2F%2Fwww.groms.de%2Fgroms%2Fwork25%2Fvortrag%2FKREFT.PDF&rft.btitle=The+Fourth+Dimension%3A+An+Overview+of+Altitudinal+Migration&rft.genre=book&rft.au=Kreft%2C+Stefan&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text">Cocker, 2005. p. 455</span></li>
<li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"><span class="citation journal">Helm B, Gwinner E (2006). <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1420642" >"Migratory Restlessness in an Equatorial Nonmigratory Bird"</a>. <i>PLoS Biol.</i> <b>4</b> (4): e110. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1371%2Fjournal.pbio.0040110" >10.1371/journal.pbio.0040110</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1420642" >1420642</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/16555925" >16555925</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=4&rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1420642&rft.atitle=Migratory+Restlessness+in+an+Equatorial+Nonmigratory+Bird&rft.genre=book&rft.aulast=Helm+B%2C+Gwinner+E&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2006&rft.pages=e110&rft.jtitle=PLoS+Biol.&rft.issue=4&rft.btitle=Migratory+Restlessness+in+an+Equatorial+Nonmigratory+Bird&rft.au=Helm+B%2C+Gwinner+E&rft_id=info%3Adoi%2F10.1371%2Fjournal.pbio.0040110&rft_id=info%3Apmid%2F16555925&rft_id=info%3Apmc%2F1420642&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><span class="citation journal">Diego Rubolini, Fernando Spina and Nicola Saino (2004). <a rel="nofollow" class="external text" href="http://beheco.oxfordjournals.org/cgi/content/abstract/15/4/592" >"Protandry and sexual dimorphism in trans-Saharan migratory birds"</a>. <i>Behavioral Ecology</i> <b>15</b> (4): 592–601. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1093%2Fbeheco%2Farh048" >10.1093/beheco/arh048</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=15&rft_id=http%3A%2F%2Fbeheco.oxfordjournals.org%2Fcgi%2Fcontent%2Fabstract%2F15%2F4%2F592&rft.atitle=Protandry+and+sexual+dimorphism+in+trans-Saharan+migratory+birds&rft.genre=book&rft.aulast=Diego+Rubolini%2C+Fernando+Spina+and+Nicola+Saino&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2004&rft.pages=592%E2%80%93601&rft.jtitle=Behavioral+Ecology&rft.issue=4&rft.btitle=Protandry+and+sexual+dimorphism+in+trans-Saharan+migratory+birds&rft.au=Diego+Rubolini%2C+Fernando+Spina+and+Nicola+Saino&rft_id=info%3Adoi%2F10.1093%2Fbeheco%2Farh048&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
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<li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><span class="citation book">Ketterson, E.D. and V. Nolan Jr. (1990). <a rel="nofollow" class="external text" href="http://www.webcitation.org/5nRF4ThAw" >"Site attachment and site fidelity in migratory birds: experimental evidence from the field and analogies from neurobiology."</a> (PDF). In E. Gwinner. <i>Bird Migration</i>. Springer Verlag. pp. 117–129. Archived from <a rel="nofollow" class="external text" href="http://www.indiana.edu/~kettlab/ellen/pubs/KettersonNolan1990.pdf" >the original</a> on 2010-02-10.</span><span title="ctx_ver=Z39.88-2004&rft.pages=117%E2%80%93129&rft_id=http%3A%2F%2Fwww.indiana.edu%2F~kettlab%2Fellen%2Fpubs%2FKettersonNolan1990.pdf&rft.atitle=Bird+Migration.&rft.genre=bookitem&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.btitle=Site+attachment+and+site+fidelity+in+migratory+birds%3A+experimental+evidence+from+the+field+and+analogies+from+neurobiology.&rft.aulast=Ketterson%2C+E.D.+and+V.+Nolan+Jr.&rft.date=1990&rft.pub=Springer+Verlag&rft.au=Ketterson%2C+E.D.+and+V.+Nolan+Jr.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><span class="citation journal">Thorup, Kasper, Thomas Alerstam, Mikael Hake and Nils Kjelle (2003). <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1698035" >"Bird orientation: compensation for wind drift in migrating raptors is age dependent"</a>. <i>Proc. R. Soc. Lond. B (Suppl.)</i> <b>270</b> (Suppl 1): S8–S11. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1098%2Frsbl.2003.0014" >10.1098/rsbl.2003.0014</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1698035" >1698035</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/12952622" >12952622</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=270&rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1698035&rft.atitle=Bird+orientation%3A+compensation+for+wind+drift+in+migrating+raptors+is+age+dependent&rft.genre=book&rft.aulast=Thorup%2C+Kasper%2C+Thomas+Alerstam%2C+Mikael+Hake+and+Nils+Kjelle&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2003&rft.pages=S8%E2%80%93S11&rft.jtitle=Proc.+R.+Soc.+Lond.+B+%28Suppl.%29&rft.issue=Suppl+1&rft.btitle=Bird+orientation%3A+compensation+for+wind+drift+in+migrating+raptors+is+age+dependent&rft.au=Thorup%2C+Kasper%2C+Thomas+Alerstam%2C+Mikael+Hake+and+Nils+Kjelle&rft_id=info%3Adoi%2F10.1098%2Frsbl.2003.0014&rft_id=info%3Apmid%2F12952622&rft_id=info%3Apmc%2F1698035&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
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<li id="cite_note-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-60">^</a></b></span> <span class="reference-text"><span class="citation journal">Cruden, R. W. (1966). "Birds as Agents of Long-Distance Dispersal for Disjunct Plant Groups of the Temperate Western Hemisphere". <i>Evolution</i> (Evolution, Vol. 20, No. 4) <b>20</b> (4): 517–532. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.2307%2F2406587" >10.2307/2406587</a>. <a href="JSTOR" webstripperwas="http://en.wikipedia.org/wiki/JSTOR" title="JSTOR">JSTOR</a> <a rel="nofollow" class="external text" href="http://www.jstor.org/stable/2406587" >2406587</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=20&rft.atitle=Birds+as+Agents+of+Long-Distance+Dispersal+for+Disjunct+Plant+Groups+of+the+Temperate+Western+Hemisphere&rft.genre=book&rft.jstor=2406587&rft.aulast=Cruden%2C+R.+W.&rft.pub=Evolution%2C+Vol.+20%2C+No.+4&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=1966&rft.pages=517%E2%80%93532&rft.jtitle=Evolution&rft.issue=4&rft.btitle=Birds+as+Agents+of+Long-Distance+Dispersal+for+Disjunct+Plant+Groups+of+the+Temperate+Western+Hemisphere&rft.au=Cruden%2C+R.+W.&rft_id=info%3Adoi%2F10.2307%2F2406587&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-61"><span class="mw-cite-backlink"><b><a href="#cite_ref-61">^</a></b></span> <span class="reference-text"><span class="citation journal">Ronald C. Ydenberg, Robert W. Butler, David B. Lank, Barry D. Smith and John Ireland (2004). <a rel="nofollow" class="external text" href="http://www.sfu.ca/biology/wildberg/ydenbergetal2004PRSB.pdf" >"Western sandpipers have altered migration tactics as peregrine falcon populations have recovered"</a>. <i>Proc. R. Soc. Lond. B</i> <b>271</b> (1545): 1263–1269 1263. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1098%2Frspb.2004.2713" >10.1098/rspb.2004.2713</a>. <a href="PubMed_Central" webstripperwas="http://en.wikipedia.org/wiki/PubMed_Central" title="PubMed Central">PMC</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691718" >1691718</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/15306350" >15306350</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=271&rft_id=http%3A%2F%2Fwww.sfu.ca%2Fbiology%2Fwildberg%2Fydenbergetal2004PRSB.pdf&rft.atitle=Western+sandpipers+have+altered+migration+tactics+as+peregrine+falcon+populations+have+recovered&rft.genre=book&rft.aulast=Ronald+C.+Ydenberg%2C+Robert+W.+Butler%2C+David+B.+Lank%2C+Barry+D.+Smith+and+John+Ireland&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2004&rft.pages=1263%E2%80%931269+1263&rft.jtitle=Proc.+R.+Soc.+Lond.+B&rft.issue=1545&rft.btitle=Western+sandpipers+have+altered+migration+tactics+as+peregrine+falcon+populations+have+recovered&rft.au=Ronald+C.+Ydenberg%2C+Robert+W.+Butler%2C+David+B.+Lank%2C+Barry+D.+Smith+and+John+Ireland&rft_id=info%3Adoi%2F10.1098%2Frspb.2004.2713&rft_id=info%3Apmid%2F15306350&rft_id=info%3Apmc%2F1691718&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-62"><span class="mw-cite-backlink"><b><a href="#cite_ref-62">^</a></b></span> <span class="reference-text"><span class="citation journal">Greenwood, Jeremy J. D. (2007). "Citizens, science and bird conservation". <i>J. Ornithol .</i> <b>148</b> (Suppl 1): S77–S124. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1007%2Fs10336-007-0239-9" >10.1007/s10336-007-0239-9</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=148&rft.atitle=Citizens%2C+science+and+bird+conservation&rft.genre=book&rft.aulast=Greenwood&rft.aufirst=Jeremy+J.+D.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2007&rft.pages=S77%E2%80%93S124&rft.jtitle=J.+Ornithol+.&rft.issue=Suppl+1&rft.btitle=Citizens%2C+science+and+bird+conservation&rft.au=Greenwood%2C+Jeremy+J.+D.&rft_id=info%3Adoi%2F10.1007%2Fs10336-007-0239-9&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text">Spencer, R. (1985) <i>Marking</i>. In: Campbell. B. & Lack, E. 1985. <i>A dictionary of birds</i>. British Ornithologists' Union. London, pp. 338–341.</span></li>
<li id="cite_note-64"><span class="mw-cite-backlink"><b><a href="#cite_ref-64">^</a></b></span> <span class="reference-text"><span class="citation journal">Keith Hobson, Leonard Wassenaar (1997). "Linking breeding and wintering grounds of neotropical migrant songbirds using stable hydrogen isotopic analysis of feathers". <i>Oecologia</i> <b>109</b>: 142–148. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1007%2Fs004420050068" >10.1007/s004420050068</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=109&rft.atitle=Linking+breeding+and+wintering+grounds+of+neotropical+migrant+songbirds+using+stable+hydrogen+isotopic+analysis+of+feathers&rft.genre=book&rft.aulast=Keith+Hobson%2C+Leonard+Wassenaar&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Linking+breeding+and+wintering+grounds+of+neotropical+migrant+songbirds+using+stable+hydrogen+isotopic+analysis+of+feathers&rft.jtitle=Oecologia&rft.pages=142%E2%80%93148&rft.date=1997&rft.au=Keith+Hobson%2C+Leonard+Wassenaar&rft_id=info%3Adoi%2F10.1007%2Fs004420050068&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-65"><span class="mw-cite-backlink"><b><a href="#cite_ref-65">^</a></b></span> <span class="reference-text"><span class="citation journal">Gabriel Bowen, Leonard Wassenaar, Keith Hobson (2005). "Global application of stable hydrogen and oxygen isotopes to wildlife forensics". <i>Oecologia</i> <b>143</b> (3): 337–348. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1007%2Fs00442-004-1813-y" >10.1007/s00442-004-1813-y</a>. <a href="PubMed_Identifier.html" webstripperwas="/wiki/PubMed_Identifier" title="PubMed Identifier" class="mw-redirect">PMID</a> <a rel="nofollow" class="external text" href="http://www.ncbi.nlm.nih.gov/pubmed/15726429" >15726429</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=143&rft.atitle=Global+application+of+stable+hydrogen+and+oxygen+isotopes+to+wildlife+forensics&rft.genre=book&rft.aulast=Gabriel+Bowen%2C+Leonard+Wassenaar%2C+Keith+Hobson&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2005&rft.pages=337%E2%80%93348&rft.jtitle=Oecologia&rft.issue=3&rft.btitle=Global+application+of+stable+hydrogen+and+oxygen+isotopes+to+wildlife+forensics&rft.au=Gabriel+Bowen%2C+Leonard+Wassenaar%2C+Keith+Hobson&rft_id=info%3Adoi%2F10.1007%2Fs00442-004-1813-y&rft_id=info%3Apmid%2F15726429&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-66"><span class="mw-cite-backlink"><b><a href="#cite_ref-66">^</a></b></span> <span class="reference-text"><span class="citation journal">Farnsworth, A., Gauthreaux, S.A., and van Blaricom, D.; Gauthreaux (2004). <a rel="nofollow" class="external text" href="http://virtual.clemson.edu/birdrad/pubs/Farnsworth,Gauthreaux,van%20Blaricom.pdf" >"A comparison of nocturnal call counts of migrating birds and reflectivity measurements on Doppler radar"</a> (PDF). <i>Journal of Avian Biology</i> <b>35</b> (4): 365–369. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1111%2Fj.0908-8857.2004.03180.x" >10.1111/j.0908-8857.2004.03180.x</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=35&rft_id=http%3A%2F%2Fvirtual.clemson.edu%2Fbirdrad%2Fpubs%2FFarnsworth%2CGauthreaux%2Cvan%2520Blaricom.pdf&rft.atitle=A+comparison+of+nocturnal+call+counts+of+migrating+birds+and+reflectivity+measurements+on+Doppler+radar&rft.genre=book&rft.aulast=Farnsworth%2C+A.%2C+Gauthreaux%2C+S.A.%2C+and+van+Blaricom%2C+D.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2004&rft.pages=365%E2%80%93369&rft.jtitle=Journal+of+Avian+Biology&rft.issue=4&rft.btitle=A+comparison+of+nocturnal+call+counts+of+migrating+birds+and+reflectivity+measurements+on+Doppler+radar&rft.au=Farnsworth%2C+A.%2C+Gauthreaux%2C+S.A.%2C+and+van+Blaricom%2C+D.&rft.au=Gauthreaux&rft_id=info%3Adoi%2F10.1111%2Fj.0908-8857.2004.03180.x&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-67"><span class="mw-cite-backlink"><b><a href="#cite_ref-67">^</a></b></span> <span class="reference-text"><span class="citation book">Liechti, F. (1996). <i>Instructions to count nocturnal bird migration by watching the full moon</i>. <a href="Sempach_Bird_Observatory" webstripperwas="http://en.wikipedia.org/wiki/Sempach_Bird_Observatory" title="Sempach Bird Observatory">Schweizerische Vogelwarte</a>, CH-6204 Sempach, Switzerland.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Liechti%2C+F.&rft.pub=Schweizerische+Vogelwarte%2C+CH-6204+Sempach%2C+Switzerland&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=1996&rft.btitle=Instructions+to+count+nocturnal+bird+migration+by+watching+the+full+moon.&rft.genre=book&rft.au=Liechti%2C+F.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-68"><span class="mw-cite-backlink"><b><a href="#cite_ref-68">^</a></b></span> <span class="reference-text"><span class="citation journal">Lowery, G.H. (1951). <a rel="nofollow" class="external text" href="http://www.archive.org/stream/universityofkans195103univ" >"A quantitative study of the nocturnal migration of birds"</a>. <i>University Kan. Pub. Mus. Nat. Hist.</i> <b>3</b>: 361–472.</span><span title="ctx_ver=Z39.88-2004&rft.volume=3&rft_id=http%3A%2F%2Fwww.archive.org%2Fstream%2Funiversityofkans195103univ%23page%2Fn373%2Fmode%2F1up&rft.atitle=A+quantitative+study+of+the+nocturnal+migration+of+birds&rft.genre=book&rft.aulast=Lowery%2C+G.H.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=A+quantitative+study+of+the+nocturnal+migration+of+birds&rft.jtitle=University+Kan.+Pub.+Mus.+Nat.+Hist.&rft.pages=361%E2%80%93472&rft.date=1951&rft.au=Lowery%2C+G.H.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-69"><span class="mw-cite-backlink"><b><a href="#cite_ref-69">^</a></b></span> <span class="reference-text"><span class="citation journal">Emlen, S. T. and Emlen, J. T. (1966). "A technique for recording migratory orientation of captive birds". <i>Auk</i> <b>83</b>: 361–367.</span><span title="ctx_ver=Z39.88-2004&rft.volume=83&rft.atitle=A+technique+for+recording+migratory+orientation+of+captive+birds&rft.genre=book&rft.aulast=Emlen%2C+S.+T.+and+Emlen%2C+J.+T.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=A+technique+for+recording+migratory+orientation+of+captive+birds&rft.jtitle=Auk&rft.pages=361%E2%80%93367&rft.date=1966&rft.au=Emlen%2C+S.+T.+and+Emlen%2C+J.+T.&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-70"><span class="mw-cite-backlink"><b><a href="#cite_ref-70">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="http://www.law.cornell.edu/uscode/16/ch7.html" >"Migratory bird Treaty 16 [[United States Code|USC]] 703-711; 40 Stat. 755"</a>. <i>Legal Information Institute (LII)</i>. Cornell Law School.</span><span title="ctx_ver=Z39.88-2004&rft.pub=Cornell+Law+School&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Migratory+bird+Treaty+16+USC+703-711%3B+40+Stat.+755&rft_id=http%3A%2F%2Fwww.law.cornell.edu%2Fuscode%2F16%2Fch7.html&rft.atitle=Migratory+bird+Treaty+16+USC+703-711%3B+40+Stat.+755&rft.genre=book&rft.jtitle=Legal+Information+Institute+%28LII%29&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span> <span style="font-size:100%" class="error citation-comment">Wikilink embedded in URL title (<a href="Help3ACS1_errors.html#wikilink_in_url" webstripperwas="/wiki/Help:CS1_errors#wikilink_in_url" title="Help:CS1 errors">help</a>)</span></span></li>
<li id="cite_note-71"><span class="mw-cite-backlink"><b><a href="#cite_ref-71">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="http://www.unep-aewa.org/documents/index.htm" >"African-Eurasian Migratory Waterbird Agreement"</a>.</span><span title="ctx_ver=Z39.88-2004&rft_id=http%3A%2F%2Fwww.unep-aewa.org%2Fdocuments%2Findex.htm&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=African-Eurasian+Migratory+Waterbird+Agreement&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-72"><span class="mw-cite-backlink"><b><a href="#cite_ref-72">^</a></b></span> <span class="reference-text"><span class="citation journal">Shimazaki, Hiroto; Masayuki Tamura and Hiroyoshi Higuchi (2004). <a rel="nofollow" class="external text" href="http://polaris.nipr.ac.jp/~penguin/oogataHP/pdfarticles/16p162-178.pdf" >"Migration routes and important stopover sites of endangered oriental white storks (<i>Ciconia boyciana</i>) as revealed by satellite tracking."</a> (PDF). <i>Mem <a href="Natl_Inst._Polar_Res." webstripperwas="http://en.wikipedia.org/wiki/Natl_Inst._Polar_Res." title="Natl Inst. Polar Res." class="mw-redirect">Natl Inst. Polar Res.</a>, Spec. Issue</i> <b>58</b>: 162–178.</span><span title="ctx_ver=Z39.88-2004&rft.volume=58&rft_id=http%3A%2F%2Fpolaris.nipr.ac.jp%2F~penguin%2FoogataHP%2Fpdfarticles%2F16p162-178.pdf&rft.atitle=Migration+routes+and+important+stopover+sites+of+endangered+oriental+white+storks+%28%27%27Ciconia+boyciana%27%27%29+as+revealed+by+satellite+tracking.&rft.genre=book&rft.aulast=Shimazaki%2C+Hiroto%3B+Masayuki+Tamura+and+Hiroyoshi+Higuchi&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Migration+routes+and+important+stopover+sites+of+endangered+oriental+white+storks+%28%27%27Ciconia+boyciana%27%27%29+as+revealed+by+satellite+tracking.&rft.jtitle=Mem+Natl+Inst.+Polar+Res.%2C+Spec.+Issue&rft.pages=162%E2%80%93178&rft.date=2004&rft.au=Shimazaki%2C+Hiroto%3B+Masayuki+Tamura+and+Hiroyoshi+Higuchi&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-73"><span class="mw-cite-backlink"><b><a href="#cite_ref-73">^</a></b></span> <span class="reference-text"><span class="citation journal">Catry, P., Encarnacao, V., Araujo, A., Fearon, P., Fearon, A., Armelin, M. & Delaloye, P. (2004). <a rel="nofollow" class="external text" href="http://repositorio.ispa.pt/bitstream/10400.12/1447/1/JAB%2035%20170-181.pdf" >"Are long-distance migrant passerines faithful to their stopover sites?"</a>. <i><a href="Journal_of_Avian_Biology" webstripperwas="http://en.wikipedia.org/wiki/Journal_of_Avian_Biology" title="Journal of Avian Biology">Journal of Avian Biology</a></i> <b>35</b> (2): 170–181. <a href="Digital_object_identifier.html" webstripperwas="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="http://dx.doi.org/10.1111%2Fj.0908-8857.2004.03112.x" >10.1111/j.0908-8857.2004.03112.x</a>.</span><span title="ctx_ver=Z39.88-2004&rft.volume=35&rft_id=http%3A%2F%2Frepositorio.ispa.pt%2Fbitstream%2F10400.12%2F1447%2F1%2FJAB%252035%2520170-181.pdf&rft.atitle=Are+long-distance+migrant+passerines+faithful+to+their+stopover+sites%3F&rft.genre=book&rft.aulast=Catry%2C+P.%2C+Encarnacao%2C+V.%2C+Araujo%2C+A.%2C+Fearon%2C+P.%2C+Fearon%2C+A.%2C+Armelin%2C+M.+%26+Delaloye%2C+P.&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.date=2004&rft.pages=170%E2%80%93181&rft.jtitle=Journal+of+Avian+Biology&rft.issue=2&rft.btitle=Are+long-distance+migrant+passerines+faithful+to+their+stopover+sites%3F&rft.au=Catry%2C+P.%2C+Encarnacao%2C+V.%2C+Araujo%2C+A.%2C+Fearon%2C+P.%2C+Fearon%2C+A.%2C+Armelin%2C+M.+%26+Delaloye%2C+P.&rft_id=info%3Adoi%2F10.1111%2Fj.0908-8857.2004.03112.x&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-74"><span class="mw-cite-backlink"><b><a href="#cite_ref-74">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="http://www.savingcranes.org/species/siberian.cfm" >"Siberian Crane fact sheet"</a>.</span><span title="ctx_ver=Z39.88-2004&rft_id=http%3A%2F%2Fwww.savingcranes.org%2Fspecies%2Fsiberian.cfm&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Siberian+Crane+fact+sheet&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
<li id="cite_note-75"><span class="mw-cite-backlink"><b><a href="#cite_ref-75">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="http://www.fws.gov/birds/mortality-fact-sheet.pdf" >"Fish and Wildlife Service- Bird Mortality Fact sheet"</a> (PDF).</span><span title="ctx_ver=Z39.88-2004&rft_id=http%3A%2F%2Fwww.fws.gov%2Fbirds%2Fmortality-fact-sheet.pdf&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fish+and+Wildlife+Service-+Bird+Mortality+Fact+sheet&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></span></li>
</ol>
</div>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=20" title="Edit section: Further reading">edit</a>]</span> <span class="mw-headline" id="Further_reading">Further reading</span></h2>
<ul>
<li><span class="citation journal">Alerstam, Thomas (2001). <a rel="nofollow" class="external text" href="http://www.mbfys.ru.nl/staff/j.vangisbergen/endnote/endnotepdfs/navigatie/Alerstam_detours_2001.pdf" >"Detours in bird migration"</a> (PDF). <i>Journal of Theoretical Biology</i> <b>209</b>: 319–331.</span><span title="ctx_ver=Z39.88-2004&rft.volume=209&rft_id=http%3A%2F%2Fwww.mbfys.ru.nl%2Fstaff%2Fj.vangisbergen%2Fendnote%2Fendnotepdfs%2Fnavigatie%2FAlerstam_detours_2001.pdf&rft.atitle=Detours+in+bird+migration&rft.genre=book&rft.aulast=Alerstam&rft.aufirst=Thomas&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.btitle=Detours+in+bird+migration&rft.jtitle=Journal+of+Theoretical+Biology&rft.pages=319%E2%80%93331&rft.date=2001&rft.au=Alerstam%2C+Thomas&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></li>
<li>Berthold, Peter (2001) Bird Migration: A General Survey. Second Edition. Oxford University Press. <a href="Special3ABookSources/0198507879" webstripperwas="http://en.wikipedia.org/wiki/Special:BookSources/0198507879" class="internal mw-magiclink-isbn">ISBN 0-19-850787-9</a></li>
<li><span class="citation book">Bewick, Thomas (1797–1804). <i>History of British Birds</i>. Newcastle: Beilby and Bewick.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=Bewick%2C+Thomas&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=1797%E2%80%931804&rft.pub=Beilby+and+Bewick&rft.btitle=History+of+British+Birds&rft.genre=book&rft.place=Newcastle&rft.au=Bewick%2C+Thomas&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></li>
<li>Dingle, Hugh. Migration: The Biology of Life on The Move. Oxford University Press, 1996.</li>
<li>Hobson, Keith and Wassenaar, Leonard (2008) Tracking Animal Migration with Stable Isotopes. Academic Press. <a href="Special3ABookSources/9780123738677" webstripperwas="http://en.wikipedia.org/wiki/Special:BookSources/9780123738677" class="internal mw-magiclink-isbn">ISBN 978-0-12-373867-7</a></li>
<li><a href="Scott_Weidensaul" webstripperwas="http://en.wikipedia.org/wiki/Scott_Weidensaul" title="Scott Weidensaul">Weidensaul, Scott</a>. Living On the Wind: Across the Hemisphere With Migratory Birds. Douglas & McIntyre, 1999.</li>
<li><a rel="nofollow" class="external text" href="http://publishing.royalsociety.org/annual-cycle" >Dedicated issue of <i>Philosophical Transactions B</i> on Adaptation to the Annual Cycle.</a></li>
<li><span class="citation book">White, Gilbert (1898 (first published 1789)). <i>The Natural History of Selborne</i>. Walter Scott.</span><span title="ctx_ver=Z39.88-2004&rft.aulast=White%2C+Gilbert&rft.pub=Walter+Scott&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.date=1898+%28first+published+1789%29&rft.btitle=The+Natural+History+of+Selborne&rft.genre=book&rft.au=White%2C+Gilbert&rfr_id=info:sid/en.wikipedia.org:Bird migration" class="Z3988"><span style="display:none;"> </span></span></li>
</ul>
<h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Bird_migration&action=edit&section=21" title="Edit section: External links">edit</a>]</span> <span class="mw-headline" id="External_links">External links</span></h2>
<ul>
<li><a rel="nofollow" class="external text" href="http://www.olangowildlifesanctuary.org/" >Route of East Asian Migratory Flyaway</a> Olango Wildlife Sanctuary as a refuelling station of migratory birds</li>
<li><a rel="nofollow" class="external text" href="http://www.migraction.net/" >Migraction.net</a> - Interactive database with real-time information on bird migration</li>
<li><a rel="nofollow" class="external text" href="http://orn-lab.ekol.lu.se/birdmigration" >Migration Ecology Group, Lund University, Sweden</a></li>
<li><a rel="nofollow" class="external text" href="http://www.migrate.ou.edu/" >Migrate.ou.edu</a> - Migration Interest Group: Research Applied Toward Education, USA</li>
<li><a rel="nofollow" class="external text" href="http://www.trektellen.nl/default.asp?taal=2" >Trektellen.nl</a> - Migration counts and ringing records: The Netherlands, Belgium, Great Britain, France, Germany, Spain and Portugal</li>
<li><a rel="nofollow" class="external text" href="http://www.bsc-eoc.org/national/cmmn.html" >Canadian Migration Monitoring Network (Co-ordinates bird migration monitoring stations across Canada)</a></li>
<li><a rel="nofollow" class="external text" href="http://www.sciencedaily.com/news/plants_animals/birds/" >Bird Research by Science Daily</a>- includes several articles on bird migration</li>
<li><a rel="nofollow" class="external text" href="http://www.nature.org/initiatives/programs/birds/" >The Nature Conservancy's Migratory Bird Program</a></li>
<li><a rel="nofollow" class="external text" href="http://www.scq.ubc.ca/?p=173" >The Compasses of Birds</a> - a review from the Science Creative Quarterly</li>
<li><a rel="nofollow" class="external text" href="http://www.bbc.co.uk/nature/animals/birds/supergoose/index.shtml" >BBC Supergoose</a> - satellite tagging of light-bellied brent geese</li>
<li><a rel="nofollow" class="external text" href="http://www.ospreyworld.com/soaring/index.html" >Soaring with Fidel</a> - follow the annual migration of ospreys from Cape Cod to Cuba to Venezuela</li>
<li><a rel="nofollow" class="external text" href="http://news.nationalgeographic.com/news/2002/09/0926_020927_birdmigration.html" >Birder's Journal: A Morning With Migrants</a> Nationalgeographic.com</li>
<li><a rel="nofollow" class="external text" href="http://www.swild.ch/publi/Bontadina_FunEco2003.pdf" >Bat predation on migrating birds</a></li>
<li><a rel="nofollow" class="external text" href="http://www.groms.de/" >Global Register of Migratory Species</a> - features not only birds, but other migratory vertebrates such as fishes</li>
<li><a rel="nofollow" class="external text" href="http://ebird.org/content/ebird/about/occurrence-maps/occurrence-maps" >eBird.com Occurrence Maps</a> - Occurrence maps of migrations of various species in United States</li>
<li><a rel="nofollow" class="external text" href="http://nationalzoo.si.edu/scbi/MigratoryBirds/default.cfm" >Smithsonian Migratory Bird Center</a> - "<i>Fostering greater understanding, appreciation, and protection of the grand phenomenon of bird migration.</i>"</li>
</ul>
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<li class="nv-view"><a href="Template3ASwarming" webstripperwas="http://en.wikipedia.org/wiki/Template:Swarming" title="Template:Swarming"><span title="View this template" style=";;background:none transparent;border:none;;">v</span></a></li>
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<div style="font-size:110%;"><a href="Swarm_behaviour" webstripperwas="http://en.wikipedia.org/wiki/Swarm_behaviour" title="Swarm behaviour">Swarming</a></div>
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<th scope="row" class="navbox-group"><a href="Biological_swarming" webstripperwas="http://en.wikipedia.org/wiki/Biological_swarming" title="Biological swarming" class="mw-redirect">Biological swarming</a></th>
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<ul>
<li><a href="Agent-based_model_in_biology" webstripperwas="http://en.wikipedia.org/wiki/Agent-based_model_in_biology" title="Agent-based model in biology">Agent-based model in biology</a></li>
<li><a href="Bait_ball" webstripperwas="http://en.wikipedia.org/wiki/Bait_ball" title="Bait ball">Bait ball</a></li>
<li><a href="Collective_animal_behavior" webstripperwas="http://en.wikipedia.org/wiki/Collective_animal_behavior" title="Collective animal behavior">Collective animal behavior</a></li>
<li><a href="Feeding_frenzy" webstripperwas="http://en.wikipedia.org/wiki/Feeding_frenzy" title="Feeding frenzy">Feeding frenzy</a></li>
<li><a href="Flock_(birds)" webstripperwas="http://en.wikipedia.org/wiki/Flock_(birds)" title="Flock (birds)">Flock</a></li>
<li><a href="Flocking_(behavior)" webstripperwas="http://en.wikipedia.org/wiki/Flocking_(behavior)" title="Flocking (behavior)">Flocking</a></li>
<li><a href="Herd" webstripperwas="http://en.wikipedia.org/wiki/Herd" title="Herd">Herd</a></li>
<li><a href="Herd_behavior" webstripperwas="http://en.wikipedia.org/wiki/Herd_behavior" title="Herd behavior">Herd behavior</a></li>
<li><a href="Mixed-species_foraging_flock" webstripperwas="http://en.wikipedia.org/wiki/Mixed-species_foraging_flock" title="Mixed-species foraging flock">Mixed-species foraging flock</a></li>
<li><a href="Mobbing_(animal_behavior)" webstripperwas="http://en.wikipedia.org/wiki/Mobbing_(animal_behavior)" title="Mobbing (animal behavior)">Mobbing behavior</a></li>
<li><a href="Pack_hunter" webstripperwas="http://en.wikipedia.org/wiki/Pack_hunter" title="Pack hunter">Pack hunter</a></li>
<li><a href="Patterns_of_self-organization_in_ants" webstripperwas="http://en.wikipedia.org/wiki/Patterns_of_self-organization_in_ants" title="Patterns of self-organization in ants">Patterns of self-organization in ants</a></li>
<li><a href="Shoaling_and_schooling" webstripperwas="http://en.wikipedia.org/wiki/Shoaling_and_schooling" title="Shoaling and schooling">Shoaling and schooling</a></li>
<li><a href="Sort_sol_(bird_flock)" webstripperwas="http://en.wikipedia.org/wiki/Sort_sol_(bird_flock)" title="Sort sol (bird flock)">Sort sol</a></li>
<li><a href="Swarm_behaviour" webstripperwas="http://en.wikipedia.org/wiki/Swarm_behaviour" title="Swarm behaviour">Swarming behaviour</a></li>
<li><a href="Swarming_(honey_bee)" webstripperwas="http://en.wikipedia.org/wiki/Swarming_(honey_bee)" title="Swarming (honey bee)">Swarming (honey bee)</a></li>
<li><a href="Swarming_motility" webstripperwas="http://en.wikipedia.org/wiki/Swarming_motility" title="Swarming motility">Swarming motility</a></li>
</ul>
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</td>
<td class="navbox-image" rowspan="9" style="width:0%;padding:0px 0px 0px 2px;">
<div><a href="File3AAuklet_flock_Shumagins_1986.jpg" webstripperwas="http://en.wikipedia.org/wiki/File:Auklet_flock_Shumagins_1986.jpg" class="image"><img alt="Auklet flock Shumagins 1986.jpg" src="upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Auklet_flock_Shumagins_1986.jpg/140px-Auklet_flock_Shumagins_1986.jpg" webstripperwas="http://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Auklet_flock_Shumagins_1986.jpg/140px-Auklet_flock_Shumagins_1986.jpg" width="140" height="95" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Auklet_flock_Shumagins_1986.jpg/210px-Auklet_flock_Shumagins_1986.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Auklet_flock_Shumagins_1986.jpg/280px-Auklet_flock_Shumagins_1986.jpg 2x" /></a></div>
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<tr>
<th scope="row" class="navbox-group"><a href="Animal_migration" webstripperwas="http://en.wikipedia.org/wiki/Animal_migration" title="Animal migration">Animal migration</a></th>
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<div style="padding:0em 0.25em;">
<ul>
<li><a href="Animal_migration" webstripperwas="http://en.wikipedia.org/wiki/Animal_migration" title="Animal migration">Animal migration</a></li>
<li><strong class="selflink">Bird migration</strong></li>
<li><a href="Category3ABird_migration_flyways" webstripperwas="http://en.wikipedia.org/wiki/Category:Bird_migration_flyways" title="Category:Bird migration flyways">Bird migration flyways</a></li>
<li><a href="Diel_vertical_migration" webstripperwas="http://en.wikipedia.org/wiki/Diel_vertical_migration" title="Diel vertical migration">Diel vertical migration</a></li>
<li><a href="Fish_migration" webstripperwas="http://en.wikipedia.org/wiki/Fish_migration" title="Fish migration">Fish migration</a></li>
<li><a href="Homing_(biology)" webstripperwas="http://en.wikipedia.org/wiki/Homing_(biology)" title="Homing (biology)">Homing (biology)</a></li>
<li><a href="Insect_migration" webstripperwas="http://en.wikipedia.org/wiki/Insect_migration" title="Insect migration">Insect migration</a></li>
<li><a href="Lessepsian_migration" webstripperwas="http://en.wikipedia.org/wiki/Lessepsian_migration" title="Lessepsian migration">Lessepsian migration</a></li>
<li><a href="Lepidoptera_migration" webstripperwas="http://en.wikipedia.org/wiki/Lepidoptera_migration" title="Lepidoptera migration">Lepidoptera migration</a></li>
<li><a href="Reverse_migration_(birds)" webstripperwas="http://en.wikipedia.org/wiki/Reverse_migration_(birds)" title="Reverse migration (birds)">Reverse migration</a></li>
<li><a href="Salmon_run" webstripperwas="http://en.wikipedia.org/wiki/Salmon_run" title="Salmon run">Salmon run</a></li>
<li><a href="Sardine_run" webstripperwas="http://en.wikipedia.org/wiki/Sardine_run" title="Sardine run">Sardine run</a></li>
<li><a href="Sea_turtle_migration" webstripperwas="http://en.wikipedia.org/wiki/Sea_turtle_migration" title="Sea turtle migration">Sea turtle migration</a></li>
<li><a href="Tracking_animal_migration" webstripperwas="http://en.wikipedia.org/wiki/Tracking_animal_migration" title="Tracking animal migration" class="mw-redirect">Tracking animal migration</a></li>
</ul>
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<th scope="row" class="navbox-group"><a href="Swarm_behaviour" webstripperwas="http://en.wikipedia.org/wiki/Swarm_behaviour" title="Swarm behaviour">Swarm algorithms</a></th>
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<div style="padding:0em 0.25em;">
<ul>
<li><a href="Agent-based_model" webstripperwas="http://en.wikipedia.org/wiki/Agent-based_model" title="Agent-based model">Agent-based models</a></li>
<li><a href="Ant_colony_optimization_algorithms" webstripperwas="http://en.wikipedia.org/wiki/Ant_colony_optimization_algorithms" title="Ant colony optimization algorithms">Ant colony optimization</a></li>
<li><a href="Ant_robotics" webstripperwas="http://en.wikipedia.org/wiki/Ant_robotics" title="Ant robotics">Ant robotics</a></li>
<li><a href="Artificial_Ants" webstripperwas="http://en.wikipedia.org/wiki/Artificial_Ants" title="Artificial Ants">Artificial ants</a></li>
<li><a href="Bat_algorithm" webstripperwas="http://en.wikipedia.org/wiki/Bat_algorithm" title="Bat algorithm">Bat algorithm</a></li>
<li><a href="Bees_algorithm" webstripperwas="http://en.wikipedia.org/wiki/Bees_algorithm" title="Bees algorithm">Bees algorithm</a></li>
<li><a href="Boids" webstripperwas="http://en.wikipedia.org/wiki/Boids" title="Boids">Boids</a></li>
<li><a href="Crowd_simulation" webstripperwas="http://en.wikipedia.org/wiki/Crowd_simulation" title="Crowd simulation">Crowd simulation</a></li>
<li><a href="Firefly_algorithm" webstripperwas="http://en.wikipedia.org/wiki/Firefly_algorithm" title="Firefly algorithm">Firefly algorithm</a></li>
<li><a href="Glowworm_swarm_optimization" webstripperwas="http://en.wikipedia.org/wiki/Glowworm_swarm_optimization" title="Glowworm swarm optimization">Glowworm swarm optimization</a></li>
<li><a href="Particle_swarm_optimization" webstripperwas="http://en.wikipedia.org/wiki/Particle_swarm_optimization" title="Particle swarm optimization">Particle swarm optimization</a></li>
<li><a href="Self-propelled_particles" webstripperwas="http://en.wikipedia.org/wiki/Self-propelled_particles" title="Self-propelled particles">Self-propelled particles</a></li>
<li><a href="Swarm_intelligence" webstripperwas="http://en.wikipedia.org/wiki/Swarm_intelligence" title="Swarm intelligence">Swarm intelligence</a></li>
<li><a href="Swarm_(simulation)" webstripperwas="http://en.wikipedia.org/wiki/Swarm_(simulation)" title="Swarm (simulation)">Swarm (simulation)</a></li>
</ul>
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</td>
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<td></td>
</tr>
<tr>
<th scope="row" class="navbox-group"><a href="Swarm_robotics" webstripperwas="http://en.wikipedia.org/wiki/Swarm_robotics" title="Swarm robotics">Swarm robotics</a></th>
<td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Intelligent_Small_World_Autonomous_Robots_for_Micro-manipulation" webstripperwas="http://en.wikipedia.org/wiki/Intelligent_Small_World_Autonomous_Robots_for_Micro-manipulation" title="Intelligent Small World Autonomous Robots for Micro-manipulation">I-Swarm</a></li>
<li><a href="Microbotics" webstripperwas="http://en.wikipedia.org/wiki/Microbotics" title="Microbotics">Microbotics</a></li>
<li><a href="Swarm_robotics" webstripperwas="http://en.wikipedia.org/wiki/Swarm_robotics" title="Swarm robotics">Swarm robotics</a></li>
<li><a href="Symbrion" webstripperwas="http://en.wikipedia.org/wiki/Symbrion" title="Symbrion">Symbrion</a></li>
</ul>
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<th scope="row" class="navbox-group">Related topics</th>
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<div style="padding:0em 0.25em;">
<ul>
<li><a href="Allee_effect" webstripperwas="http://en.wikipedia.org/wiki/Allee_effect" title="Allee effect">Allee effect</a></li>
<li><a href="Animal_navigation" webstripperwas="http://en.wikipedia.org/wiki/Animal_navigation" title="Animal navigation">Animal navigation</a></li>
<li><a href="Collective_intelligence" webstripperwas="http://en.wikipedia.org/wiki/Collective_intelligence" title="Collective intelligence">Collective intelligence</a></li>
<li><a href="Eusociality" webstripperwas="http://en.wikipedia.org/wiki/Eusociality" title="Eusociality">Eusociality</a></li>
<li><a href="Group_size_measures" webstripperwas="http://en.wikipedia.org/wiki/Group_size_measures" title="Group size measures">Group size measures</a></li>
<li><a href="Microbial_intelligence" webstripperwas="http://en.wikipedia.org/wiki/Microbial_intelligence" title="Microbial intelligence">Microbial intelligence</a></li>
<li><a href="Mutualism_(biology)" webstripperwas="http://en.wikipedia.org/wiki/Mutualism_(biology)" title="Mutualism (biology)">Mutualism</a></li>
<li><a href="Predator_satiation" webstripperwas="http://en.wikipedia.org/wiki/Predator_satiation" title="Predator satiation">Predator satiation</a></li>
<li><a href="Quorum_sensing" webstripperwas="http://en.wikipedia.org/wiki/Quorum_sensing" title="Quorum sensing">Quorum sensing</a></li>
<li><a href="Spatial_organization" webstripperwas="http://en.wikipedia.org/wiki/Spatial_organization" title="Spatial organization">Spatial organization</a></li>
<li><a href="Stigmergy" webstripperwas="http://en.wikipedia.org/wiki/Stigmergy" title="Stigmergy">Stigmergy</a></li>
<li><a href="Swarming_(military)" webstripperwas="http://en.wikipedia.org/wiki/Swarming_(military)" title="Swarming (military)">Swarming (military)</a></li>
<li><a href="Task_allocation_and_partitioning_of_social_insects" webstripperwas="http://en.wikipedia.org/wiki/Task_allocation_and_partitioning_of_social_insects" title="Task allocation and partitioning of social insects">Task allocation and partitioning of social insects</a></li>
</ul>
</div>
</td>
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</table>
</td>
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</table>
<table cellspacing="0" class="navbox" style="border-spacing:0;">
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<div class="noprint plainlinks hlist navbar mini">
<ul>
<li class="nv-view"><a href="Template3ABirds" webstripperwas="http://en.wikipedia.org/wiki/Template:Birds" title="Template:Birds"><span title="View this template" style=";;background:none transparent;border:none;;">v</span></a></li>
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<li class="nv-edit"><a class="external text" href="http://en.wikipedia.org/w/index.php?title=Template:Birds&action=edit" ><span title="Edit this template" style=";;background:none transparent;border:none;;">e</span></a></li>
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<div style="font-size:110%;"><a href="Bird.html" webstripperwas="/wiki/Bird" title="Bird">Birds</a> (<a href="Class_(biology).html" webstripperwas="/wiki/Class_(biology)" title="Class (biology)">class</a>: Aves)</div>
</th>
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<tr style="height:2px;">
<td></td>
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<th scope="row" class="navbox-group"><a href="Anatomy.html" webstripperwas="/wiki/Anatomy" title="Anatomy">Anatomy</a></th>
<td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Bird_anatomy" webstripperwas="http://en.wikipedia.org/wiki/Bird_anatomy" title="Bird anatomy">Bird anatomy</a></li>
<li><a href="Bird_flight" webstripperwas="http://en.wikipedia.org/wiki/Bird_flight" title="Bird flight">Flight</a></li>
<li><a href="Egg_(biology)" webstripperwas="http://en.wikipedia.org/wiki/Egg_(biology)" title="Egg (biology)">Eggs</a></li>
<li><a href="Feather" webstripperwas="http://en.wikipedia.org/wiki/Feather" title="Feather">Feathers</a></li>
<li><a href="Plumage.html" webstripperwas="/wiki/Plumage" title="Plumage">Plumage</a></li>
<li><a href="Beak" webstripperwas="http://en.wikipedia.org/wiki/Beak" title="Beak">Beak</a></li>
<li><a href="Bird_vision" webstripperwas="http://en.wikipedia.org/wiki/Bird_vision" title="Bird vision">Vision</a></li>
<li><a href="Dactyly" webstripperwas="http://en.wikipedia.org/wiki/Dactyly" title="Dactyly">Dactyly</a></li>
<li><a href="Uropygial_gland" webstripperwas="http://en.wikipedia.org/wiki/Uropygial_gland" title="Uropygial gland">Preen gland</a></li>
</ul>
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<tr style="height:2px;">
<td></td>
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<th scope="row" class="navbox-group">Behaviour</th>
<td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Bird_vocalization" webstripperwas="http://en.wikipedia.org/wiki/Bird_vocalization" title="Bird vocalization">Singing</a></li>
<li><a href="Bird_intelligence" webstripperwas="http://en.wikipedia.org/wiki/Bird_intelligence" title="Bird intelligence">Intelligence</a></li>
<li><strong class="selflink">Migration</strong></li>
<li><a href="Avian_incubation" webstripperwas="http://en.wikipedia.org/wiki/Avian_incubation" title="Avian incubation" class="mw-redirect">Incubation</a></li>
<li><a href="Brood_parasite" webstripperwas="http://en.wikipedia.org/wiki/Brood_parasite" title="Brood parasite">Brood parasites</a></li>
<li><a href="Bird_nest" webstripperwas="http://en.wikipedia.org/wiki/Bird_nest" title="Bird nest">Nesting</a></li>
<li><a href="Bird_hybrid" webstripperwas="http://en.wikipedia.org/wiki/Bird_hybrid" title="Bird hybrid">Hybrids</a></li>
</ul>
</div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<th scope="row" class="navbox-group"><a href="Evolution" webstripperwas="http://en.wikipedia.org/wiki/Evolution" title="Evolution">Evolution</a></th>
<td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Evolution_of_birds" webstripperwas="http://en.wikipedia.org/wiki/Evolution_of_birds" title="Evolution of birds">Evolution of birds</a></li>
<li><a href="Origin_of_birds" webstripperwas="http://en.wikipedia.org/wiki/Origin_of_birds" title="Origin of birds">Origin of birds</a></li>
<li><a href="Darwin$27s_finches" webstripperwas="http://en.wikipedia.org/wiki/Darwin%27s_finches" title="Darwin's finches">Darwin's finches</a></li>
<li><a href="Seabird" webstripperwas="http://en.wikipedia.org/wiki/Seabird" title="Seabird">Seabirds</a></li>
</ul>
</div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
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<tr>
<th scope="row" class="navbox-group"><br />
Subclass: <a href="Modern_birds" webstripperwas="http://en.wikipedia.org/wiki/Modern_birds" title="Modern birds">Neornithes</a><br />
(29 <a href="Order_(biology).html" webstripperwas="/wiki/Order_(biology)" title="Order (biology)">orders</a> of modern birds)</th>
<td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;"></div>
<table cellspacing="0" class="nowraplinks navbox-subgroup" style="border-spacing:0;">
<tr>
<td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px;">
<div style="padding:0em 0.25em;"></div>
<table cellspacing="0" class="nowraplinks navbox-subgroup" style="border-spacing:0;">
<tr>
<td class="navbox-abovebelow" colspan="2" style="text-align: left;;">
<div>Superorder: <a href="Palaeognathae" webstripperwas="http://en.wikipedia.org/wiki/Palaeognathae" title="Palaeognathae">Palaeognathae</a></div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Ratite" webstripperwas="http://en.wikipedia.org/wiki/Ratite" title="Ratite">Struthioniformes <small style="font-size:85%;">(ratites)</small></a></li>
<li><a href="Tinamou" webstripperwas="http://en.wikipedia.org/wiki/Tinamou" title="Tinamou">Tinamiformes <small style="font-size:85%;">(tinamous)</small></a></li>
</ul>
</div>
</td>
</tr>
</table>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0px;">
<div style="padding:0em 0.25em;"></div>
<table cellspacing="0" class="nowraplinks navbox-subgroup" style="border-spacing:0;">
<tr>
<td class="navbox-abovebelow" colspan="2" style="text-align: left;;">
<div>Superorder: <a href="Neognathae" webstripperwas="http://en.wikipedia.org/wiki/Neognathae" title="Neognathae">Neognathae</a></div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
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<tr>
<td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Anseriformes" webstripperwas="http://en.wikipedia.org/wiki/Anseriformes" title="Anseriformes">Anseriformes <small style="font-size:85%;">(waterfowl)</small></a></li>
<li><a href="Galliformes" webstripperwas="http://en.wikipedia.org/wiki/Galliformes" title="Galliformes">Galliformes <small style="font-size:85%;">(gamebirds)</small></a></li>
<li><a href="Opisthocomidae" webstripperwas="http://en.wikipedia.org/wiki/Opisthocomidae" title="Opisthocomidae">Opisthocomiformes <small style="font-size:85%;">(Hoatzin)</small></a></li>
<li><a href="Sandgrouse" webstripperwas="http://en.wikipedia.org/wiki/Sandgrouse" title="Sandgrouse">Pteroclidiformes <small style="font-size:85%;">(sandgrouses)</small></a></li>
<li><a href="Columbiformes" webstripperwas="http://en.wikipedia.org/wiki/Columbiformes" title="Columbiformes" class="mw-redirect">Columbiformes <small style="font-size:85%;">(doves and pigeons)</small></a></li>
<li><a href="Tropicbird" webstripperwas="http://en.wikipedia.org/wiki/Tropicbird" title="Tropicbird">Phaethontiformes <small style="font-size:85%;">(tropicbirds)</small></a></li>
<li><a href="Eurypygiformes" webstripperwas="http://en.wikipedia.org/wiki/Eurypygiformes" title="Eurypygiformes">Eurypygiformes <small style="font-size:85%;">(Kagu and Sunbittern)</small></a></li>
<li><a href="Mesite" webstripperwas="http://en.wikipedia.org/wiki/Mesite" title="Mesite">Mesitornithiformes <small style="font-size:85%;">(mesites)</small></a></li>
<li><a href="Grebe" webstripperwas="http://en.wikipedia.org/wiki/Grebe" title="Grebe">Podicipediformes <small style="font-size:85%;">(grebes)</small></a></li>
<li><a href="Flamingo" webstripperwas="http://en.wikipedia.org/wiki/Flamingo" title="Flamingo">Phoenicopteriformes <small style="font-size:85%;">(flamingos)</small></a></li>
<li><a href="Caprimulgiformes" webstripperwas="http://en.wikipedia.org/wiki/Caprimulgiformes" title="Caprimulgiformes">Caprimulgiformes <small style="font-size:85%;">(nightjars and relatives)</small></a></li>
<li><a href="Apodiformes" webstripperwas="http://en.wikipedia.org/wiki/Apodiformes" title="Apodiformes">Apodiformes <small style="font-size:85%;">(swifts and hummingbirds)</small></a></li>
<li><a href="Cuculiformes" webstripperwas="http://en.wikipedia.org/wiki/Cuculiformes" title="Cuculiformes">Cuculiformes <small style="font-size:85%;">(cuckoos and relatives)</small></a></li>
<li><a href="Gruiformes" webstripperwas="http://en.wikipedia.org/wiki/Gruiformes" title="Gruiformes">Gruiformes <small style="font-size:85%;">(cranes and relatives)</small></a></li>
<li><a href="Loon" webstripperwas="http://en.wikipedia.org/wiki/Loon" title="Loon">Gaviiformes <small style="font-size:85%;">(loons or divers)</small></a></li>
<li><a href="Procellariiformes" webstripperwas="http://en.wikipedia.org/wiki/Procellariiformes" title="Procellariiformes">Procellariiformes <small style="font-size:85%;">(albatrosses and petrels)</small></a></li>
<li><a href="Ciconiiformes" webstripperwas="http://en.wikipedia.org/wiki/Ciconiiformes" title="Ciconiiformes">Ciconiiformes <small style="font-size:85%;">(storks)</small></a></li>
<li><a href="Pelecaniformes" webstripperwas="http://en.wikipedia.org/wiki/Pelecaniformes" title="Pelecaniformes">Pelecaniformes <small style="font-size:85%;">(pelicans and relatives)</small></a></li>
<li><a href="Suliformes" webstripperwas="http://en.wikipedia.org/wiki/Suliformes" title="Suliformes">Suliformes <small style="font-size:85%;">(cormorants and relatives)</small></a></li>
<li><a href="Penguin" webstripperwas="http://en.wikipedia.org/wiki/Penguin" title="Penguin">Sphenisciformes <small style="font-size:85%;">(penguins)</small></a></li>
<li><a href="Charadriiformes" webstripperwas="http://en.wikipedia.org/wiki/Charadriiformes" title="Charadriiformes">Charadriiformes <small style="font-size:85%;">(gulls and relatives)</small></a></li>
<li><a href="Accipitriformes" webstripperwas="http://en.wikipedia.org/wiki/Accipitriformes" title="Accipitriformes">Accipitriformes <small style="font-size:85%;">(eagles and hawks)</small></a></li>
<li><a href="Trogon" webstripperwas="http://en.wikipedia.org/wiki/Trogon" title="Trogon">Trogoniformes <small style="font-size:85%;">(trogons and quetzals)</small></a></li>
<li><a href="Mousebird" webstripperwas="http://en.wikipedia.org/wiki/Mousebird" title="Mousebird">Coliiformes <small style="font-size:85%;">(mousebirds)</small></a></li>
<li><a href="Owl" webstripperwas="http://en.wikipedia.org/wiki/Owl" title="Owl">Strigiformes <small style="font-size:85%;">(owls)</small></a></li>
<li><a href="Cuckoo_Roller" webstripperwas="http://en.wikipedia.org/wiki/Cuckoo_Roller" title="Cuckoo Roller">Leptosomatiformes <small style="font-size:85%;">(Cuckoo Roller)</small></a></li>
<li><a href="Coraciiformes" webstripperwas="http://en.wikipedia.org/wiki/Coraciiformes" title="Coraciiformes">Coraciiformes <small style="font-size:85%;">(kingfishers and relatives)</small></a></li>
<li><a href="Piciformes" webstripperwas="http://en.wikipedia.org/wiki/Piciformes" title="Piciformes">Piciformes <small style="font-size:85%;">(woodpeckers and relatives)</small></a></li>
<li><a href="Cariamiformes" webstripperwas="http://en.wikipedia.org/wiki/Cariamiformes" title="Cariamiformes">Cariamiformes <small style="font-size:85%;">(seriemas and relatives)</small></a></li>
<li><a href="Falconiformes" webstripperwas="http://en.wikipedia.org/wiki/Falconiformes" title="Falconiformes">Falconiformes <small style="font-size:85%;">(falcons and relatives)</small></a></li>
<li><a href="Parrot" webstripperwas="http://en.wikipedia.org/wiki/Parrot" title="Parrot">Psittaciformes <small style="font-size:85%;">(parrots)</small></a></li>
<li><a href="Passerine.html" webstripperwas="/wiki/Passerine" title="Passerine">Passeriformes <small style="font-size:85%;">(perching birds)</small></a></li>
</ul>
</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<th scope="row" class="navbox-group"><a href="List_of_fossil_birds" webstripperwas="http://en.wikipedia.org/wiki/List_of_fossil_birds" title="List of fossil birds">Fossil birds</a></th>
<td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><i><a href="Archaeopteryx" webstripperwas="http://en.wikipedia.org/wiki/Archaeopteryx" title="Archaeopteryx">Archaeopteryx</a></i></li>
<li><a href="Enantiornithes" webstripperwas="http://en.wikipedia.org/wiki/Enantiornithes" title="Enantiornithes">Enantiornithes</a></li>
<li><a href="Hesperornithes" webstripperwas="http://en.wikipedia.org/wiki/Hesperornithes" title="Hesperornithes">Hesperornithes</a></li>
</ul>
</div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<th scope="row" class="navbox-group">Human–bird interaction</th>
<td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="Bird_ringing" webstripperwas="http://en.wikipedia.org/wiki/Bird_ringing" title="Bird ringing">Ringing</a></li>
<li><a href="Ornithology" webstripperwas="http://en.wikipedia.org/wiki/Ornithology" title="Ornithology">Ornithology</a></li>
<li><a href="Bird_collections" webstripperwas="http://en.wikipedia.org/wiki/Bird_collections" title="Bird collections">Bird collections</a></li>
<li><a href="Birdwatching" webstripperwas="http://en.wikipedia.org/wiki/Birdwatching" title="Birdwatching">Birdwatching</a></li>
<li><a href="Bird_feeding" webstripperwas="http://en.wikipedia.org/wiki/Bird_feeding" title="Bird feeding">Bird feeding</a></li>
<li><a href="Bird_conservation" webstripperwas="http://en.wikipedia.org/wiki/Bird_conservation" title="Bird conservation">Conservation</a></li>
<li><a href="Aviculture" webstripperwas="http://en.wikipedia.org/wiki/Aviculture" title="Aviculture">Aviculture</a></li>
<li><a href="Waterfowl_hunting" webstripperwas="http://en.wikipedia.org/wiki/Waterfowl_hunting" title="Waterfowl hunting">Waterfowl hunting</a></li>
<li><a href="Cockfighting" webstripperwas="http://en.wikipedia.org/wiki/Cockfighting" title="Cockfighting" class="mw-redirect">Cockfighting</a></li>
<li><a href="Pigeon_racing" webstripperwas="http://en.wikipedia.org/wiki/Pigeon_racing" title="Pigeon racing">Pigeon racing</a></li>
<li><a href="Falconry" webstripperwas="http://en.wikipedia.org/wiki/Falconry" title="Falconry">Falconry</a></li>
<li><a href="Pheasantry" webstripperwas="http://en.wikipedia.org/wiki/Pheasantry" title="Pheasantry">Pheasantry</a></li>
<li><a href="Oology" webstripperwas="http://en.wikipedia.org/wiki/Oology" title="Oology">Egg Collecting</a></li>
</ul>
</div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<th scope="row" class="navbox-group">Lists</th>
<td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;">
<div style="padding:0em 0.25em;">
<ul>
<li><a href="List_of_birds" webstripperwas="http://en.wikipedia.org/wiki/List_of_birds" title="List of birds">Families and orders</a></li>
<li><a href="List_of_bird_genera" webstripperwas="http://en.wikipedia.org/wiki/List_of_bird_genera" title="List of bird genera">Genera</a></li>
<li><a href="Lists_of_birds_by_population" webstripperwas="http://en.wikipedia.org/wiki/Lists_of_birds_by_population" title="Lists of birds by population">Lists by population</a></li>
<li><a href="Lists_of_birds_by_region" webstripperwas="http://en.wikipedia.org/wiki/Lists_of_birds_by_region" title="Lists of birds by region">Lists by region</a></li>
<li><a href="List_of_extinct_birds" webstripperwas="http://en.wikipedia.org/wiki/List_of_extinct_birds" title="List of extinct birds">Extinct birds</a></li>
<li><a href="Late_Quaternary_prehistoric_birds" webstripperwas="http://en.wikipedia.org/wiki/Late_Quaternary_prehistoric_birds" title="Late Quaternary prehistoric birds">Late Quaternary prehistoric birds</a></li>
<li><a href="Sibley-Ahlquist_taxonomy_of_birds" webstripperwas="http://en.wikipedia.org/wiki/Sibley-Ahlquist_taxonomy_of_birds" title="Sibley-Ahlquist taxonomy of birds" class="mw-redirect">Sibley-Ahlquist taxonomy</a></li>
</ul>
</div>
</td>
</tr>
<tr style="height:2px;">
<td></td>
</tr>
<tr>
<td class="navbox-abovebelow" colspan="2">
<div>
<ul>
<li><a href="Category3ABirds" webstripperwas="http://en.wikipedia.org/wiki/Category:Birds" title="Category:Birds">Category</a></li>
<li><a href="Portal3ABirds" webstripperwas="http://en.wikipedia.org/wiki/Portal:Birds" title="Portal:Birds">Portal</a></li>
<li><a href="Outline_of_birds" webstripperwas="http://en.wikipedia.org/wiki/Outline_of_birds" title="Outline of birds">Outline</a></li>
</ul>
</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
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