Editing Common tern (section)

==Distribution and habitat==
[[File:Sterna hirundo - Boat Harbour.jpg|thumb|Non-breeding adult in Australia]]
[[File:Sterna hirundo Hailuoto 20160803 02.jpg|thumb|A pair of juveniles in Marjaniemi, [[Hailuoto]], Finland]]

Most populations of the common tern are strongly migratory, wintering south of their temperate and subarctic Northern Hemisphere breeding ranges. First summer birds usually remain in their wintering quarters, although a few return to breeding colonies some time after the arrival of the adults.<ref name=harrison/> In North America, the common tern breeds along the Atlantic coast from [[Labrador]] to [[North Carolina]], and inland throughout much of Canada east of the [[Rocky Mountains]]. In the United States, some breeding populations can also be found in the states bordering the [[Great Lakes]], and locally on the [[Gulf of Mexico|Gulf]] coast.<ref name=cuthbert4/> There are small, only partially migratory, colonies in the [[Caribbean]]; these are in The Bahamas and Cuba,<ref name=raff>Raffaele et al. (2003) p. 292.</ref> and off Venezuela in the [[Los Roques archipelago|Los Roques]] and [[Las Aves archipelago]]s.<ref name=hilty>Hilty (2002) p. 310.</ref>

New World birds winter along both coasts of Central and South America, to Argentina on the east coast and to northern Chile on the west coast.<ref name=harrison>Harrison (1998) pp. 370–374.</ref><ref name=cuthbert4>Cuthbert (2003) p. 4.</ref> Records from South America and the Azores show that some birds may cross the Atlantic in both directions on their migration.<ref name=lima>Lima (2006) p. 132.</ref><ref name=neves>{{cite journal |last=Neves |first=Verónica C |author2=Bremer, R Esteban |author3=Hays, Helen W |year=2002 |title=Recovery in Punta Rasa, Argentina of Common Terns banded in the Azores archipelago, North Atlantic |journal=Waterbirds |volume=25 |issue=4 |pages=459–461 |url=http://www.horta.uac.pt/intradop/images/stories/perspages/veronicaneves/09_Waterbirds2002.pdf |doi=10.1675/1524-4695(2002)025[0459:RIPRAO]2.0.CO;2 |s2cid=86369861 |access-date=17 February 2012 |archive-date=9 August 2017 |archive-url=https://web.archive.org/web/20170809230052/http://www.horta.uac.pt/intradop/images/stories/perspages/veronicaneves/09_Waterbirds2002.pdf |url-status=live }}</ref>

The common tern breeds across most of Europe, with the highest numbers in the north and east of the continent. There are small populations on the north African coast, and in the [[Azores]], [[Canary Islands]] and [[Madeira]]. Most winter off western or southern Africa, birds from the south and west of Europe tending to stay north of the [[equator]] and other European birds moving further south.<ref name= snow779>Snow & Perrin (1998) pp. 779–782.</ref> The breeding range continues across the temperate and [[taiga]] zones of Asia, with scattered outposts on the [[Persian Gulf]] and the coast of Iran.<ref name=hume39>Hume (1993) pp. 39–41.</ref> Small populations breed on islands off Sri Lanka,<ref name=hoffmann>{{cite journal |author=Hoffmann, Thilo W |year=1990 |title=Breeding of the Common Tern ''Sterna hirundo'' in Sri Lanka |journal=Journal of the Bombay Natural History Society |volume=87 |issue=1 |pages=68–72 |url=https://biodiversitylibrary.org/page/48806758 |access-date=27 December 2017 |archive-date=26 October 2020 |archive-url=https://web.archive.org/web/20201026105813/https://www.biodiversitylibrary.org/page/48806758 |url-status=live }}</ref><ref name=hoffmann2>{{cite journal |author=Hoffmann, Thilo W |year=1992 |title=Confirmation of the breeding of the Common Tern ''Sterna hirundo'' Linn. in Sri Lanka |journal=Journal of the Bombay Natural History Society |volume=89 |issue=2 |pages=251–252 |url=https://biodiversitylibrary.org/page/48732715 |access-date=27 December 2017 |archive-date=3 July 2022 |archive-url=https://web.archive.org/web/20220703024047/https://www.biodiversitylibrary.org/page/48732715 |url-status=live }}</ref> and in the [[Ladakh]] region of the Tibetan plateau.<ref name=ras>Rasmussen & Anderton (2005) pp. 194–195.</ref> Western Asian birds winter in the northern [[Indian Ocean]],<ref name=harrison/><ref>{{Cite journal|last=Khan|first=Asif N.|date=1 April 2015|title=Record of Common Tern ''Sterna hirundo'' from Andaman & Nicobar Islands, India|journal=Journal of the Bombay Natural History Society |volume=112|issue=1|page=30|doi=10.17087/jbnhs/2015/v112i1/92329|doi-access=free}}</ref> and ''S.{{nbs}}h.{{nbs}}tibetana'' appears to be common off [[East Africa]] during the Northern Hemisphere winter.<ref name=Zimmerman>Zimmerman et al. (2010) p. 354.</ref> Birds from further north and east in Asia, such as ''S.{{nbs}}h.{{nbs}}longipennis'', move through Japan, Thailand and the western [[Pacific Ocean|Pacific]] as far as southern Australia.<ref name=harrison/> There are small and erratic colonies in [[West Africa]], in Nigeria and Guinea-Bissau, unusual in that they are within what is mainly a wintering area.<ref name=hume39/> Only a few common terns have been recorded in New Zealand,<ref name=Robertson>Robertson & Heather (2005) p. 126.</ref> and this species' status in [[Polynesia]] is unclear.<ref name=watling170>Watling (2003) pp. 204–205.</ref> A bird [[Bird ringing|ringed]] at the nest in Sweden was found dead on [[Stewart Island]], New Zealand, five months later, having flown an estimated 25,000{{nbs}}km (15,000{{nbs}}mi).<ref name=newton>Newton (2010) pp. 150–151.</ref>

As long-distance migrants, common terns sometimes occur well outside their normal range. Stray birds have been found inland in Africa (Zambia and Malawi), and on the Maldives and Comoros islands;<ref name=BirdLife2>{{cite web |title=BirdLife International Species factsheet: ''Sterna hirundo'', additional information |publisher=BirdLife International |url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=3270&m=1 |access-date=26 January 2012 |archive-date=4 September 2011 |archive-url=https://web.archive.org/web/20110904192654/http://www.birdlife.org/datazone/speciesfactsheet.php?id=3270&m=1 }}</ref> the nominate subspecies has reached Australia,<ref name=Simpson>Simpson & Day (2010) p. 110.</ref> the Andes, and the interior of South America.<ref name=peru/><ref name=Costanzo>{{cite journal |last=DiCostanzo |first=Joseph |year=1978 |title=Occurrences of the Common Tern in the interior of South America |journal=Bird-Banding |volume=49 |issue=3 |pages=248–251 |doi=10.2307/4512366|jstor=4512366}}</ref> Asian ''S.{{nbs}}h.{{nbs}}longipennis'' has recent records from western Europe.<ref name=BW>{{cite journal |last=Darby |first=Chris |year=2011 |title=Eastern Common Terns in Suffolk and Belgium |journal=Birding World |volume=24 |issue=12 |pages=511–512}}</ref>

The common tern breeds over a wider range of habitats than any of its relatives, nesting from the [[taiga]] of Asia to tropical shores,<ref name=hume30>Hume (1993) pp. 30–37.</ref> and at altitudes up to {{convert|2000|m|abbr=on}} in Armenia, and {{convert|4800|m|abbr=on}} in Asia.<ref name=snow779/> It avoids areas which are frequently exposed to excessive rain or wind, and also icy waters, so it does not breed as far north as the Arctic tern. The common tern breeds close to freshwater or the sea on almost any open flat habitat, including sand or [[shingle beach]]es, firm dune areas, [[salt marsh]], or, most commonly, islands. Flat grassland or [[heath]], or even large flat rocks may be suitable in an island environment.<ref name=hume30/> In mixed colonies, common terns will tolerate somewhat longer ground vegetation than Arctic terns, but avoid the even taller growth acceptable to roseate terns; the relevant factor here is the different leg lengths of the three species.<ref name=Fisher/> Common terns adapt readily to artificial floating rafts, and may even nest on flat factory roofs.<ref name=hume30/> Unusual nest sites include hay bales, a stump {{convert|0.6|m|ft|0|abbr=on}} above the water, and floating logs or vegetation. There is a record of a common tern taking over a [[spotted sandpiper]] nest and laying its eggs with those of the [[wader]].<ref name=ontario/> Outside the breeding season, all that is needed in terms of habitat is access to fishing areas, and somewhere to land. In addition to natural beaches and rocks, boats, buoys and piers are often used both as perches and as night-time roosts.<ref name=hume30/>