Editing Caspian tern

{{Short description|Species of bird}}
{{Speciesbox
| image = Sterna-caspia-010.jpg
| image_caption = Breeding plumage, Canada
| image2 = Caspian tern (Hydroprogne caspia) non-breeding.jpg
| image2_caption = Non-breeding plumage, [[The Gambia]]
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=iucn>{{cite journal |author=BirdLife International |author-link=BirdLife International |title=''Hydroprogne caspia'' |journal=[[IUCN Red List of Threatened Species]] |volume=2015 |page=e.T22694524A84639220 |year=2015 | doi = 10.2305/IUCN.UK.2015.RLTS.T22694524A84639220.en|doi-access=free }}</ref>
| genus = Hydroprogne
| parent_authority = [[Johann Jakob Kaup|Kaup]], 1829
| species = caspia
| authority = ([[Peter Simon Pallas|Pallas]], 1770)
| synonyms=''Sterna caspia'' <br />
''Hydroprogne tschegrava''<br />
''Helopus caspius''
| range_map = Hydroprogne caspia map.svg
}}

The '''Caspian tern''' ('''''Hydroprogne caspia''''')<ref name=bridge/> is a species of [[tern]], with a [[cosmopolitan distribution|subcosmopolitan]] but scattered distribution. Despite its extensive range, it is [[monotypic]] of its genus, and has no accepted [[subspecies]].<ref name=lynx/> The genus name is from [[Ancient Greek]] ''hudro-'', "water-", and [[Latin]] ''progne'', "[[swallow]]". The specific ''caspia'' is from Latin and, like the English name, refers to the [[Caspian Sea]].<ref name=job>{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/helmdictionarysc00jobl_997 | url-access= limited | publisher= Christopher Helm | location = London | isbn = 978-1-4081-2501-4 | pages = [https://archive.org/details/helmdictionarysc00jobl_997/page/n93 93], 197}}</ref>

==Description==
It is the world's largest tern with a length of {{convert|48|–|60|cm|in|abbr=on}}, a wingspan of {{convert|127|–|145|cm|in|abbr=on}} and a weight of {{convert|530|-|782|g|abbr=on}}.<ref name=lynx/><ref name=WildAboutTerns/> Adult birds have black legs, and a long thick red-orange bill with a small black tip. They have a white head with a black cap and white neck, belly, and tail.<ref name="R">{{Cite book|page=118|title=New Holland Field Guide to the Birds of South East Asia|first=Craig|last=Robson|date=2007|publisher=New Holland|location=London|isbn=978-1843307464}}</ref> The upper wings and back are pale grey; the underwings are pale with dark primary feathers. In-flight, the tail is less forked than other terns, and wingtips are black on the underside.<ref name=lynx/> In winter, the black cap is still present (unlike many other terns), but with some white streaking on the forehead. The call is a loud [[heron|heron-like]] croak.<ref name=mullarney/><ref name="R"/>

==Distribution and habitat==
Their breeding habitat is large lakes and ocean coasts in [[North America]] (including the [[Great Lakes]]), and locally in [[Europe]] (mainly around the [[Baltic Sea]] and [[Black Sea]]), [[Palearctic|Asia]], [[Africa]], and [[Australasia]] ([[Australia]] and [[New Zealand]]). North American birds [[Bird migration|migrate]] to southern coasts, the [[West Indies]] and northernmost [[South America]]. European and Asian birds spend the non-breeding season in the [[Old World]] tropics.<ref name="R"/> African and Australasian birds are resident or disperse over short distances.<ref name=lynx/>

In 2016, a nest of the Caspian tern was found in the [[Cape Krusenstern National Monument]] in northwestern [[Alaska]], 1,000 miles further north than any previous sighting.  This development was part of a general trend in Alaska of species moving to the north, a tendency ascribed to [[global warming]].<ref>{{cite news| last = Milman | first = Oliver | title = Terns follow record warm temperatures in 'shock' migration to north of Alaska| newspaper = [[The Guardian]]| date = 23 September 2016| url = https://www.theguardian.com/environment/2016/sep/23/terns-migration-alaska  | access-date = 2016-09-27}}</ref>

The global population is about 50,000 pairs; numbers in most regions are stable, but the Baltic Sea population (1400–1475 pairs in the early 1990s) is declining and of conservation concern.<ref name=lynx/><ref name=bwpc/>

The Caspian tern is one of the species to which the ''Agreement on the Conservation of African-Eurasian Migratory Waterbirds'' ([[AEWA]]) applies.

==Behaviour==

===Feeding===
They feed mainly on [[fish]], which they dive for, hovering high over the water and then plunging. They also occasionally eat large [[insect]]s, the young and eggs of other birds and rodents. They may fly up to {{convert|60|km|mi|abbr=on}} from the breeding colony to catch fish; they often fish on freshwater lakes as well as at sea.<ref name=lynx/><ref name=mullarney/>

===Breeding===
[[File:Hydroprogne caspia MWNH 0386.JPG|thumb|Egg, Collection [[Museum Wiesbaden]]]]
Breeding is in spring and summer, with one to three pale blue-green eggs, with heavy brown spotting, being laid. They nest either together in colonies, or singly in mixed colonies of other tern and [[gull]] species. The nest is on the ground among gravel and sand, or sometimes on vegetation; incubation lasts for 26–28 days. The chicks are variable in plumage pattern, from pale creamy to darker grey-brown; this variation assists adults in recognizing their own chicks when returning to the colony from feeding trips. Fledging occurs after 35–45 days.<ref name=lynx/>

==Gallery==
<gallery>
File:Caspian Tern takeoff RWD.jpg|Preparing for takeoff
File:Caspian tern in flight at DeKorte Park (42079).jpg|Caspian tern in flight
File:Two caspian terns.png|Two Caspian terns in flight
File:Caspian Tern in flight in New Zealand.png|In flight In New Zealand
</gallery>

== References ==
{{Reflist|refs=
<ref name=bridge>{{cite journal |last1=Bridge |first1=E.S. |last2=Jones |first2=A.W. |last3=Baker |first3=A.J. |year=2005 |title=A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution |journal=Molecular Phylogenetics and Evolution |volume=35 |issue=2 |pages=459–469 |pmid=15804415 |doi=10.1016/j.ympev.2004.12.010|bibcode=2005MolPE..35..459B }}</ref>

<ref name=bwpc>{{Cite book |last1=Snow |first1=D.W. |last2=Perrins |first2=C.M. |year=1998 |title=The Birds of the Western Palearctic |edition=Concise |publisher=Oxford University Press |isbn=978-0-19-854099-1}}</ref>

<ref name=lynx>{{cite book |title=Handbook of the Birds of the World |editor-last1=del Hoyo |editor-first1=J. |editor-last2=Elliot |editor-first2=A. |editor-last3=Sargatal |editor-first3=J. |year=1996 |publisher=[[Lynx Edicions]] |location=[[Barcelona]] |isbn=978-84-87334-20-7 |volume=3 |page=[https://archive.org/details/handbookofbirdso0001unse/page/645 645] |title-link=Handbook of the Birds of the World }}</ref>

<ref name=mullarney>{{Cite book |last1=Mullarney |first1=K. |last2=Svensson |first2=L. |last3=Zetterström |first3=D. |last4=Grant |first4=P.J. |year=1999 |title=Collins Bird Guide |publisher=Collins |isbn=978-0-00-219728-1}}</ref>

<ref name=WildAboutTerns>{{cite web |url=http://www.environment.nsw.gov.au/resources/nature/08261WildAboutTerns.pdf |title=Wild About Terns: Looking After Our Shorebirds |publisher=Department of the Environment and Climate Change NSW}}</ref>
}}

== External links ==
{{Commons category|Hydroprogne caspia}}
{{Wikispecies|Hydroprogne caspia}}
* [http://sabap2.adu.org.za/docs/sabap1/322.pdf Caspian Tern species text in The Atlas of Southern African Birds]
* {{BirdLife|22694524|Hydroprogne caspia}}
* {{Avibase|name=Hydroprogne caspia}}
* {{InternetBirdCollection|caspian-tern-hydroprogne-caspia}}
* {{VIREO|caspian+tern}}
* {{IUCN_Map|22694524/166281584|Hydroprogne caspia}}
* {{Xeno-canto species|Hydroprogne|caspia|Caspian tern}}
* {{field guide birds of the world|Hydroprogne caspia}}
* {{ARKive}}

{{Charadriiformes|L.|state=collapsed}}
{{Taxonbar|from=Q27129}}
{{Authority control}}

[[Category:Terns|Caspian tern]]
[[Category:Birds of Central Asia]]
[[Category:Birds of Eurasia]]
[[Category:Birds of Madagascar]]
[[Category:Birds of North America]]
[[Category:Birds of the Dominican Republic]]
[[Category:Birds of Oceania]]
[[Category:Birds of West Africa]]
[[Category:Birds of Africa]]
[[Category:Birds described in 1770|Caspian tern]]
[[Category:Cosmopolitan birds]]
[[Category:Holarctic birds]]