Difference between revisions of "Gull-billed Tern" - BirdForum Opus

Latest revision as of 01:07, 23 February 2024

G. n. nilotica : Breeding plumage
Photo © by scottishdude
Goa, India, March 2009

Gelochelidon nilotica

Sterna nilotica

Identification

G. n. nilotica : Non-breeding plumage
Photo © by Alok Tewari
Jamnagar, Coastal Gujarat, India, Jan-2016

Length 33–43 cm (13-17 in), wingspan 80-95 cm.
A stocky but long-legged, gull-like tern with a stout, all-black bill. In flight, broad-winged, reminiscent of a small gull or a large marsh tern.

cap black in summer, reduced to a small black ear patch in winter
tail only shallowly forked
upperparts, including wings, pale silvery-grey
tips of primaries dark, generally giving a dark trailing edge
rump and tail pale silvery grey
underparts white
legs black, long

Juvenile with buffy-brown to blackish 'V'-marks above, otherwise similar to winter adult, but smaller.

Variation

European birds average larger and heavier than birds in the Americas.

Similar Species

G. n. nilotica Juvenile
Photo © by AJDH
Al Khobar, Saudi Arabia, July 2006

Australian Tern is larger with a larger bill, back and wings very pale with white rather than grey rump and upper tail. Non-breeding: larger black ear coverts which are square-ended.
Sandwich Tern has a yellow tip to the black bill, shorter legs, relatively longer, narrower wings in flight, shaggy crest, and white rump and tail; in winter plumage, retains black at rear of head, less so over ear coverts.
Whiskered Tern has similar structure, and plumage pattern in winter, but is substantially smaller - though can be hard to tell where size not easily judged - and with slightly more extensive black on rear of head.
In winter plumage, Forster's Tern has similar, though more obvious, black ear patches.

Distribution

Like the Caspian Tern, widespread but patchy distributed, breeding in temperate and subtropical regions globally, though not extending so far north as Caspian Tern, in Europe only to 54°N (in northern Germany, though formerly also bred in western Denmark at 56°N), and in North America to 41°N (on Long Island, New York).

Also local in Asia, South America, and as non-breeding in Australia. Migratory in the temperate Northern Hemisphere, wintering south to the tropics; southernmost populations in South America disperse northward even if not too far.

An annual vagrant in the British Isles, mostly to the south coast.

Taxonomy

Adult/G. n. nilotica in flight
Photo © by Kevin Wade
Laguna Salada, Málaga, Spain, April 2018

Australian Tern has been split from this species.

This species was in the past included in the genus Sterna.

Subspecies

Subspecies G. n. Aranea
Photo © by NJLarsen
Pitt Street Causeway, Charleston, South Carolina, 1 May 2023

Morphological differences between races are slight, involving overall size and bill size.

Clements recognises the following subspecies [1]:

G. n. nilotica: Europe, western and southern Asia; winters tropical Africa and Persian Gulf to India
G. n. affinis: Eastern Asia from Transbaikalia to Manchuria and eastern China; winters South-eastern Asia
G. n. aranea: Eastern USA to Greater Antilles and Yucatán; winters to Brazil and Peru
G. n. vanrossemi: California to northern Baja and north-western Mexico; winters to Ecuador
G. n. gronvoldi: Coasts and rivers of French Guiana to north-eastern Argentina

Race affinis was formerly called addenda.

Habitat

Breeds on sandy shores of the sea and large lakes, but - uniquely for a tern - feeds mainly over land, typically over coastal marshes and fields. Also overwinters near inland waters (lagoons, marshes, lakes, rivers etc).

Behaviour

Diet

The diet consists mostly of large insects, but also feeds on frogs and small mammals.

Breeding

Breeds colonially in a variety of habitats: lakes, fresh and saline marshes. Also mountain lakes to a height of around 2000m.

References

Clements, J. F., P. C. Rasmussen, T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, A. Spencer, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2023. The eBird/Clements checklist of Birds of the World: v2023. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/
Gill, F, D Donsker, and P Rasmussen (Eds). 2023. IOC World Bird List (v 13.2). Doi 10.14344/IOC.ML.13.2. http://www.worldbirdnames.org/
Collins Pocket Guide to British Birds 1966
Grant, P.J., K. Mullarney, L. Svensson, D. Zetterstrom (1999) Collins Bird Guide: The Most Complete Field Guide to the Birds of Britain and Europe. Harpercollins Pub Ltd ISBN 0 00 219728 6
Collins Bird Guide ISBN 0 00 219728 6

List of references

Recommended Citation

BirdForum Opus contributors. (2024) Gull-billed Tern. In: BirdForum, the forum for wild birds and birding. Retrieved 3 May 2024 from https://www.birdforum.net/opus/Gull-billed_Tern

External Links

Search for photos of Gull-billed Tern in the gallery

Search for videos of Gull-billed Tern in the gallery

GSearch checked for 2020 platform.1

@@ Line 1: / Line 1: @@
-[[Image:Gull-billed_tern2.jpg|thumb|550px|right|Photo of breeding plumaged bird by {{user|scottishdude|scottishdude}}<br />Goa, [[India]]]]
+[[Image:Gull-billed_tern2.jpg|thumb|550px|right|''G. n. nilotica'' : Breeding plumage<br />Photo &copy; by {{user|scottishdude|scottishdude}}<br />Goa, [[India]], March 2009]]
-;[[:Category:Sterna|Sterna]] nilotica
-''Gelochelidon nilotica''
+;[[Category:Gelochelidon]] [[:Category:Gelochelidon|Gelochelidon]] nilotica
+''Sterna nilotica''
 ==Identification==
-cm<br />
+[[Image:gull-billed_tern_alok.JPG|thumb|350px|right|''G. n. nilotica'' : Non-breeding plumage<br />Photo &copy; by {{user|aloktewari|Alok Tewari}}<br />Jamnagar, Coastal Gujarat, [[India]], Jan-2016]]
-*Black bill
+Length 33–43 cm (13-17 in), wingspan 80-95 cm.<br />
-*Black cap
+A stocky but long-legged, gull-like tern with a stout, all-black bill. In flight, broad-winged, reminiscent of a small gull or a large marsh tern.
-*Grey upperparts
-*Black legs
+* cap black in summer, reduced to a small black ear patch in winter
+* tail only shallowly forked
+* upperparts, including wings, pale silvery-grey
+* tips of primaries dark, generally giving a dark trailing edge
+* rump and tail pale silvery grey
+* underparts white
+* legs black, long
+Juvenile with buffy-brown to blackish 'V'-marks above, otherwise similar to winter adult, but smaller.
+====Variation====
+[[Europe]]an birds average larger and heavier than birds in the [[America]]s.
 ====Similar Species====
-The [[Sandwich Tern]] has a black bill with a yellow tip.
+[[Image:33708AJD1756 800w.jpg|thumb|350px|right|''G. n. nilotica'' Juvenile<br />Photo &copy; by {{user|AJDH|AJDH}}<br />Al Khobar, [[Saudi Arabia]], July 2006]]
-[[Image:Gull-billed_Tern.jpg|thumb|350px|right|Photo of winter plumaged bird by {{user|Gashead|Gashead}}<br />Dubai creek, [[United Arab Emirates]].]]
+*[[Australian Tern]] is larger with a larger bill, back and wings very pale with white rather than grey rump and upper tail. Non-breeding: larger black ear coverts which are square-ended.
+*[[Sandwich Tern]] has a yellow tip to the black bill, shorter legs, relatively longer, narrower wings in flight, shaggy crest, and white rump and tail; in winter plumage, retains black at rear of head, less so over ear coverts.
+*[[Whiskered Tern]] has similar structure, and plumage pattern in winter, but is substantially smaller - though can be hard to tell where size not easily judged - and with slightly more extensive black on rear of head.
+*In winter plumage, [[Forster's Tern]] has similar, though more obvious, black ear patches.
 ==Distribution==
-Almost world-wide.
+Like the [[Caspian Tern]], widespread but patchy distributed, breeding in temperate and subtropical regions globally, though not extending so far north as Caspian Tern, in [[Europe]] only to 54°N (in northern [[Germany]], though formerly also bred in western [[Denmark]] at 56°N), and in [[North America]] to 41°N (on Long Island, [[New York]]).
+Also local in [[Asia]], [[South America]], and as non-breeding in [[Australia]]. Migratory in the temperate Northern Hemisphere, wintering south to the tropics; southernmost populations in [[South America]] disperse northward even if not too far.
+An annual vagrant in the [[British Isles]], mostly to the south coast.
-Annual passage migrant mostly to the south coast of the [[British Isles]]
 ==Taxonomy==
-Six subspecies are recognized<sup>[[#References|[1]]]</sup>:
+[[IMAGE:Gbt8.jpg|thumb|350px|right|Adult/G. n. nilotica in flight<br />Photo &copy; by {{user|Kevin+Wade|Kevin Wade}}<br />Laguna Salada, Málaga, [[Spain]], April 2018]]
-*''nilotica'':
+[[Australian Tern]] has been split from this species.
-:* [[Palearctic]]; winters tropical [[Africa]] and Persian Gulf to [[India]]
-*''addenda'':
+This species was in the past included in the genus ''[[:Category:Sterna|Sterna]]''.
-:* Transbaikalia to Manchuria and eastern [[China]]; winters South-eastern [[Asia]]
+====Subspecies====
-*''macrotarsa'':
+[[File:Gulf-billed_Tern_ssp-Gn-Aranea_NIELS.jpg|thumb|350px|right|Subspecies G. n. Aranea<br />Photo &copy; by {{user|njlarsen|NJLarsen}}<br /> Pitt Street Causeway, Charleston, [[South Carolina]], 1 May 2023]]
-:* [[Australia]] (except arid areas)
+Morphological differences between races are slight, involving overall size and bill size.
-*''arenea'':
-:* Eastern [[US]] to [[Greater Antilles]] and Yucatán; winters to [[Brazil]] and [[Peru]]
+Clements recognises the following subspecies [[#References|[1]]]:
-*''groenvoldi'':
+*''G. n. nilotica'': [[Europe]], western and southern [[Asia]]; winters tropical [[Africa]] and Persian Gulf to [[India]]
-:* Coasts and rivers of [[French Guiana]] to north-eastern [[Argentina]]
+*''G. n. affinis'': Eastern Asia from Transbaikalia to Manchuria and eastern [[China]]; winters South-eastern [[Asia]]
-*''vanrossemi'':
+*''G. n. aranea'': Eastern [[USA]] to [[Greater Antilles]] and Yucatán; winters to [[Brazil]] and [[Peru]]
-:* [[California]] to northern Baja and north-western [[Mexico]]; winters to [[Ecuador]]
+*''G. n. vanrossemi'': [[California]] to northern Baja and north-western [[Mexico]]; winters to [[Ecuador]]
+*''G. n. gronvoldi'': Coasts and rivers of [[French Guiana]] to north-eastern [[Argentina]]
+Race ''affinis'' was formerly called ''addenda''.
-Several newer resourses have reassigned this species to genus ''[[: Category:Gelochelidon|Gelochelidon]]''; if more follow the lead, Opus will as well.
-[[Image:33708AJD1756 800w.jpg|thumb|350px|right|Photo by {{user|AJDH|AJDH}}<br />Al Khobar, [[Saudi Arabia]], July 2006]]
 ==Habitat==
-Prefers sandy seashore but also overwinters near inland waters (lagoons, marshes, lakes, rivers etc).
+Breeds on sandy shores of the sea and large lakes, but - uniquely for a tern - feeds mainly over land, typically over coastal marshes and fields. Also overwinters near inland waters (lagoons, marshes, lakes, rivers etc).
 ==Behaviour==
 ====Diet====
-The diet consists mostly of insects, but also feeds on frogs and small mammals.
+The diet consists mostly of large insects, but also feeds on frogs and small mammals.
 ====Breeding====
 Breeds colonially in a variety of habitats: lakes, fresh and saline marshes. Also mountain lakes to a height of around 2000m.
 ==References==
-# Clements, James F. 2007. ''The Clements Checklist of Birds of the World''. 6th ed., with updates to October 2007. Ithaca: Cornell University Press. ISBN 9780801445019
+#{{Ref-Clements6thOct23}}#{{Ref-GillDonskerRasmussen22V13.2}}#Collins Pocket Guide to British Birds 1966
-#Collins Pocket Guide to British Birds 1966
+#{{Ref-Grantetal99}}#Collins Bird Guide ISBN 0 00 219728 6
-#Collins Field Guide 5th Edition
-#Collins Bird Guide ISBN 0 00 219728 6
 {{ref}}
 ==External Links==
-{{GSearch|tern+nilotica}} <!--- Comment: the search term changed to find birds with both genus names --->
+{{GSearch|"Gelochelidon nilotica" {{!}} "Sterna nilotica" {{!}} "Gull-billed Tern"}}
-[[Category:Birds]] [[Category:Sterna]]
+<br />
+{{VSearch|"Gelochelidon nilotica" {{!}} "Sterna nilotica" {{!}} "Gull-billed Tern"}}
+{{GS-checked}}1
+<br />
+<br />
+[[Category:Birds]] [[Category:Gelochelidon]] [[Category:Videos]]