Editing Bird migration (section)

==Long-distance migration==

The typical image of migration is of northern land birds, such as [[swallow]]s (Hirundinidae) and birds of prey, making long flights to the tropics. However, many [[Holarctic realm|Holarctic]] [[wildfowl]] and [[Fringillidae|finch]] (Fringillidae) species winters in the [[North Temperate Zone]], in regions with milder winters than their summer breeding grounds. For example, the [[pink-footed goose]] migrates from [[Iceland]] to [[Great Britain|Britain]] and neighbouring countries, whilst the [[dark-eyed junco]] migrates from [[subarctic climate|subarctic]] and [[tundra climate|arctic climates]] to the contiguous United States<ref>{{Cite web|title=Dark-eyed Junco Identification
| work= All About Birds
| publisher= Cornell Lab of Ornithology|url=https://www.allaboutbirds.org/guide/Dark-eyed_Junco/id|access-date=2023-02-20}}</ref> and the American goldfinch <!--''Spinus tristis''--> from taiga to wintering grounds extending from the [[Southern United States|American South]] northwestward to [[Western Oregon]].<ref>{{Cite web|title=American Goldfinch Identification
| work=All About Birds
| publisher=Cornell Lab of Ornithology|url=https://www.allaboutbirds.org/guide/American_Goldfinch/id|access-date=2023-02-20}}</ref> Some ducks, such as the [[garganey]] ''Spatula querquedula'', move completely or partially into the tropics. The [[European pied flycatcher]] ''Ficedula hypoleuca'' follows this migratory trend, breeding in Asia and Europe and wintering in Africa.

Migration routes and wintering grounds are both genetically and traditionally determined depending on the social system of the species. In long-lived, social species such as [[white stork]]s ''(Ciconia ciconia),'' flocks are often led by the oldest members and young storks learn the route on their first journey.<ref>{{cite journal |last1=Chernetsov |first1=N. |last2=Berthold |first2=P. |last3=Querner |first3=U. |year=2004 |title=Migratory orientation of first-year white storks (''Ciconia ciconia''): inherited information and social interactions |journal=Journal of Experimental Biology |volume=207 |issue=6 |pages=937–943 |doi=10.1242/jeb.00853 |pmid=14766952 |doi-access=free|bibcode=2004JExpB.207..937C }}</ref> In short-lived species that migrate alone, such as the [[Eurasian blackcap]] ''Sylvia atricapilla'' or the [[yellow-billed cuckoo]] ''Coccyzus americanus'', first-year migrants follow a genetically determined route that is alterable with selective breeding.<ref>{{cite journal |last=Sutherland |first=W. J. |year=1998 |title=Evidence for flexibility and constraint in migration systems |journal=Journal of Avian Biology |volume=29 |issue=4 |pages=441–446 |doi=10.2307/3677163 |jstor=3677163}}</ref><ref>{{cite journal |last=Berthold |first=P. |author2=Helbig, A. J. |author3=Mohr, G. |author4=Querner, U. |year=1992 |title=Rapid microevolution of migratory behaviour in a wild bird species |journal=Nature |volume=360 |issue=6405 |pages=668–670 |doi=10.1038/360668a0 |bibcode=1992Natur.360..668B |s2cid=4372637}}</ref>

Many migration routes of long-distance migratory birds are circuitous due to evolutionary history: the breeding range of [[Northern wheatear]]s ''Oenanthe oenanthe'' has expanded to cover the entire Northern Hemisphere, but the species still migrates up to 14,500&nbsp;km to reach ancestral wintering grounds in [[sub-Saharan Africa]] rather than establish new wintering grounds closer to breeding areas.<ref>{{cite journal |last=Bairlein |first=F. |author2=Norris, D. R. |author3=Nagel, R. |author4=Bulte, M. |author5=Voigt, C. C. |author6=Fox, J. W. |author7=Hussell, D. J. T. |display-authors=et al |year=2012 |title=Cross-hemisphere migration of a 25 g songbird |journal=Biology Letters |volume=8 |issue=4 |pages=505–507 |doi=10.1098/rsbl.2011.1223 |pmid=22337504 |pmc=3391447}}</ref>

A migration route often does not follow the most direct line between breeding and wintering grounds. Rather, it could follow a hooked or arched line, with detours around geographical barriers or towards suitable stopover habitat. For most land birds, such barriers could consist of large water bodies or high mountain ranges, a lack of stopover or feeding sites, or a lack of [[thermal column]]s (important for broad-winged birds).<ref name="Berthold" /> 
Conversely, in [[water birds|water-birds]], large areas of land without wetlands offering suitable feeding sites may present a barrier, and detours avoiding such barriers are observed. For example, [[Brant (goose)|brent geese]] ''Branta bernicla bernicla'' migrating between the [[Taymyr Peninsula]] and the [[Wadden Sea]] travel via low-lying coastal feeding-areas on the [[White Sea]] and the [[Baltic Sea]] rather than directly across the [[Arctic Ocean]] and the [[Scandinavia]]n mainland.<ref>{{cite web |url=http://www.geese.org/gsg/Gorid.htm |title=The Riddle of the White Sea |publisher=Geese.org |date=1999 |access-date=10 April 2014 |last=Green |first=Martin |archive-date=29 July 2020 |archive-url=https://web.archive.org/web/20200729101527/https://www.geese.org/gsg/Gorid.htm |url-status=dead }}<!--journal refs at website--></ref>
<ref name=Ganter2000>
{{cite journal
| last1      = Ganter
| first1     = Barbara
| date       = 2000
| title      = Seagrass (''Zostera'' spp.) as food for brent geese (''Branta bernicla''): an overview
| url        = https://link.springer.com/content/pdf/10.1007/s101520050003.pdf
| journal    = Helgoland Marine Research
| volume = 54
| issue      = 2–3
| pages      = 63–70
| doi        = 10.1007/s101520050003
| bibcode = 2000HMR....54...63G
| s2cid = 3832705
| access-date = 8 December 2021
}} (breeding and wintering ranges with subspecies' flyway maps; diet)</ref>

[[Great snipe]]s make non-stop flights of 4,000–7,000&nbsp;km, lasting 60–90 h, during which they change their average cruising heights from 2,000 m (above sea level) at night to around 4,000 m during daytime.<ref>{{Cite journal|last1=Lindström|first1=Åke|last2=Alerstam|first2=Thomas|last3=Andersson|first3=Arne|last4=Bäckman|first4=Johan|last5=Bahlenberg|first5=Peter|last6=Bom|first6=Roeland|last7=Ekblom|first7=Robert|last8=Klaassen|first8=Raymond H.G.|last9=Korniluk|first9=Michał|last10=Sjöberg|first10=Sissel|last11=Weber|first11=Julia K.M.|date=August 2021|title=Extreme altitude changes between night and day during marathon flights of great snipes|journal=Current Biology|volume=31|issue=15|pages=3433–3439.e3|doi=10.1016/j.cub.2021.05.047|pmid=34197730|issn=0960-9822|doi-access=free|bibcode=2021CBio...31E3433L }}</ref>

===In waders===
[[File:BartailedGodwit24.jpg |right |thumb |[[Bar-tailed godwit]]]]

A similar situation occurs with [[wader]]s (called ''shorebirds'' in North America). Many species, such as [[dunlin]] ''Calidris alpina''<ref>{{cite web |url=http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3056 |title=Species factsheet: Dunlin Calidris alpina |publisher=BirdLife International |date=2014 |access-date=19 June 2014 |archive-date=12 August 2014 |archive-url=https://web.archive.org/web/20140812214214/http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3056 |url-status=dead }}</ref> and [[western sandpiper]] ''Calidris mauri'',<ref>{{cite web |url=http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3044 |title=Species factsheet: Western Sandpiper Calidris mauri |publisher=BirdLife International |date=2014 |access-date=19 June 2014 |archive-date=12 August 2014 |archive-url=https://web.archive.org/web/20140812214035/http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3044 |url-status=dead }}</ref> undertake long movements from their Arctic breeding grounds to warmer locations in the same hemisphere, but others such as [[semipalmated sandpiper]] ''C. pusilla'' travel longer distances to the tropics in the Southern Hemisphere.<ref>{{cite web |url=http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3043 |title=Species factsheet: Semipalmated Sandpiper Calidris pusilla |publisher=BirdLife International |date=2014 |access-date=19 June 2014 |archive-date=12 August 2014 |archive-url=https://web.archive.org/web/20140812224300/http://www.birdlife.org.uk/datazone/speciesfactsheet.php?id=3043 |url-status=dead }}</ref>

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 [[Bay of Fundy]] and [[Delaware River|Delaware Bay]].<ref>{{cite journal |last=Sprague |first=A. J. |author2=D. J. Hamilton |author3=A. W. Diamond |title=Site Safety and Food Affect Movements of Semipalmated Sandpipers (Calidris pusilla) Migrating Through the Upper Bay of Fundy |journal=Avian Conservation and Ecology |year=2008 |volume=3 |issue=2 |doi=10.5751/ACE-00252-030204 |doi-access=free}}</ref><ref>{{cite journal |last=Kathleen E. Clark, Lawrence J. Niles and Joanna Burger |title=Abundance and Distribution of Migrant Shorebirds in Delaware Bay |journal=The Condor |volume=95 |issue=3 |pages=694–705 |url=http://www.state.nj.us/dep/fgw/ensp/pdf/literature/abundance-distribution_shorebirds_delbay.pdf |doi=10.2307/1369612 |jstor=1369612 |year=1993}}</ref>

Some [[bar-tailed godwit]]s ''Limosa lapponica baueri'' have the longest known non-stop flight of any migrant, flying 11,000&nbsp;km from [[Alaska]] to their [[New Zealand]] non-breeding areas.<ref>{{cite journal |title=Crossing the ultimate ecological barrier: evidence for an 11,000&nbsp;km-long nonstop flight from Alaska to New Zealand and Eastern Australia by Bar-tailed Godwits |last=Gill |first=Robert E. Jr. |author2=Theunis Piersma |author3=Gary Hufford |author4=Rene Servranckx |author5=Adrian Riegen |journal=The Condor |year=2005 |volume=107 |issue=1 |pages=1–20 |doi=10.1650/7613 |hdl=11370/531c931d-e4bd-427c-a6ad-1496c81d44c0 |s2cid=84878931 |type=Submitted manuscript |url=https://www.rug.nl/research/portal/en/publications/crossing-the-ultimate-ecological-barrier(531c931d-e4bd-427c-a6ad-1496c81d44c0).html|doi-access=free }}</ref> Prior to migration, 55 percent of their bodyweight is stored as fat to fuel this uninterrupted journey.

===In seabirds===
[[File:2009 07 02 - Arctic tern nesting on Farne Islands.JPG |thumb |right |The [[Arctic tern]] migrates the greatest distance of any bird.]]

[[Seabird]] migration is similar in pattern to those of the waders and waterfowl. Some, such as the [[black guillemot]] ''Cepphus grylle'' and some [[gull]]s, are quite sedentary; others, such as most [[tern]]s and [[auk]]s breeding in the temperate northern hemisphere, move varying distances south in the northern winter. The [[Arctic tern]] ''Sterna paradisaea'' 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.<ref name=Cramp>{{cite book |title=Birds of the Western Palearctic |editor-last=Cramp |editor-first=S. |year=1985 |pages=87–100 |publisher=Oxford University Press |isbn=978-0-19-857507-8}}</ref> One Arctic tern, [[Bird ringing|ringed]] (banded) as a chick on the [[Farne Islands]] in [[Northumberland]] off the [[Great Britain|British]] east coast, reached [[Melbourne]], [[Australia]] in just three months from fledging, a sea journey of over {{convert|22,000|km|nmi|sigfig=2|abbr=on}}, while another also from the Farne Islands with a [[light level geolocator]] tag 'G82' covered a staggering {{convert|96,000|km|nmi|sigfig=2|abbr=on}} in just 10 months from the end of one breeding season to the start of the next, travelling not just the length of the Atlantic Ocean and the width of the Indian Ocean, but also half way across the South Pacific to the boundary between the [[Ross Sea|Ross]] and [[Amundsen Sea]]s before returning back west along the Antarctic coast and back up the Atlantic.<ref name="BBC">{{cite news |last1=BBC News |title=Arctic tern in record-breaking migration from Farne Islands |url=https://www.bbc.co.uk/news/uk-england-tyne-36466763 |access-date=2024-07-24 |agency=BBC |date=7 June 2016}}</ref><ref name="Redfern">{{cite journal |last1=Redfern |first1=Chris |last2=Bevan |first2=Richard M. |title=Use of sea ice by arctic terns Sterna paradisaea in Antarctica and impacts of climate change |journal=Journal of Avian Biology |date=2020 |volume=51 |issue=2 |doi=10.1111/jav.02318 |url=https://nsojournals.onlinelibrary.wiley.com/doi/epdf/10.1111/jav.02318 |access-date=24 July 2024|url-access=subscription }}</ref> Many tubenosed birds breed in the southern hemisphere and migrate north in the southern winter.<ref>{{cite web |url=http://pubs.usgs.gov/circ/c1198/chapters/150-161_Seabirds.pdf |title=Seabirds |publisher=USGS |work=Circular 1198 |date=2001 |access-date=19 June 2014 |last=Pyle |first=Peter |pages=154}}</ref>

The most pelagic species, mainly in the 'tubenose' order [[Procellariiformes]], are great wanderers, and the [[albatross]]es 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 among the longest-distance migrants; [[sooty shearwater]]s ''Puffinus griseus'' nesting on the [[Falkland Islands]] migrate {{convert|14,000|km|nmi|sigfig=2|abbr=on}} between the breeding colony and the [[Atlantic Ocean|North Atlantic Ocean]] off [[Norway]]. Some [[Manx shearwater]]s ''Puffinus puffinus'' 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 {{convert|8|e6km|e6nmi|round=0.5|abbr=off}} during its over-50-year lifespan.<ref>{{cite web |url=http://edition.cnn.com/2002/WORLD/europe/04/18/britain.bird/index.html?iref=allsearch |title=Oldest bird clocks 5 million miles |publisher=CNN.com |date=18 April 2002 |access-date=31 March 2013 |author=Anon}}</ref>

===Diurnal migration in large birds using thermals===
[[File:Vulture 19o05.jpg |right |thumb |[[Griffon vulture]] soaring]]

Some large broad-winged birds rely on [[thermal]] columns of rising hot air to enable them to soar. These include many [[bird of prey|birds of prey]] such as [[vulture]]s, [[eagle]]s, and [[buzzard]]s, but also [[stork]]s. 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 Sea|Mediterranean]] and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large [[Bird of prey|raptors]] and storks pass through areas such as the [[Strait of Messina]],<ref>{{cite web |url=http://www.surfbirds.com/mb/Features/messina/messina-0302.html |title=European Birding Hot Spot: The Strait of Messina, southern Italy |last=Corso |first=Andrea}}</ref> [[Gibraltar]], [[Falsterbo]], and the [[Bosphorus]] at migration times. More common species, such as the [[European honey buzzard]] ''Pernis apivorus'', can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can cause funnelling, particularly of large diurnal migrants, as in the [[Central America]]n migratory bottleneck. The [[Batumi]] bottleneck in the Caucasus is one of the heaviest migratory funnels on earth, created when hundreds of thousands of soaring birds avoid flying over the Black Sea surface and across high mountains.<ref name=Gavashelishvili11>{{cite journal |last=Maanen |first=E. van |author2=Goradze, I. |author3=Gavashelishvili, A. |author4=Goradze, R. |year=2001 |title=Opinion: Trapping and hunting of migratory raptors in western Georgia |journal=Bird Conservation International |volume=11 |issue=2 |pages=77–92 |doi=10.1017/S095927090100017X |doi-broken-date=1 November 2024 |doi-access=free}}</ref> Birds of prey such as honey buzzards which migrate using thermals lose only 10 to 20% of their weight during migration, which may explain why they forage less during migration than do smaller birds of prey with more active flight such as falcons, hawks and harriers.<ref>Gensbol, B; (1984) Collins Guide to the Birds of Prey of Britain and Europe, p.28</ref>

[[File:The natural terrace of Mount Dinnammare on the Strait of Messina, sicily .JPG|thumb|The bottleneck of the [[Strait of Messina]], point of transit of the migrations, seen from the [[Peloritani]] mountains, [[Sicily]]]]

From observing the migration of eleven soaring bird species over the Strait of Gibraltar, species which did not advance their autumn migration dates were those with declining breeding populations in Europe.<ref>{{cite journal |last=Panuccio |first=M. |author2=Martín, B. |author3=Onrubia, A. |author4=Ferrer, M.  |year=2017 |title=Long-term changes in autumn migration dates at the Strait of Gibraltar reflect population trends of soaring birds |journal=Ibis |volume=159 |pages=55–65 |doi=10.1111/ibi.12420 |issue=1 |hdl=10261/141899 |hdl-access=free}}</ref>

[[File:Rubythroathummer65.jpg|thumb|[[Ruby-throated hummingbird]]]]