Glaucous gull
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The glaucous gull (Larus hyperboreus) is a large gull, the second-largest gull in the world. The genus name is from Latin Template:Lang, which appears to have referred to a gull or other large seabird. The specific name Template:Lang is Latin for "northern" from the Ancient Greek Huperboreoi people from the far north <ref name=job>Template:Cite book</ref> "Glaucous" is from Latin Template:Lang and denotes the grey colour of the gull.<ref name=OED>Template:Cite OED</ref> An older English name for this species is burgomaster.<ref name="Audubon">Template:Cite web</ref>
Distribution
This gull breeds in Arctic regions of the Northern Hemisphere and winters south to shores of the Holarctic. It is migratory, wintering from in the North Atlantic and North Pacific Oceans as far south as the British Isles and northernmost states of the United States, also on the Great Lakes. A few birds sometimes reach the southern USA and northern Mexico.
Description
This is a large and powerful gull, second-largest of all gull species and very pale in all plumage, with no black on either the wings or the tail. Adults are pale grey above, with a thick, yellow bill. Juveniles are very pale grey with a pink and black bill. This species is considerably larger, bulkier, and thicker-billed than the similar Iceland gull, and can sometimes equal the size of the great black-backed gull, the oft-titled largest gull species. In some areas, glaucous gulls are about the same weight as great black-backed gulls or even heavier, and their maximum weight is greater.<ref name=CRC2/> They can weigh from Template:Convert, with the sexes previously reported to average Template:Convert in males and Template:Convert in females.<ref name=CRC/><ref name=Olsen/> At the colony on Coats Island in Canada, the gulls are nearly 15% heavier than some other known populations, with a mean weight Template:Convert in five males and Template:Convert in seven females. One other study claimed even higher weights for glaucous gulls, as on Wrangel Island, 9 males reportedly averaged Template:Convert and Template:Convert in six females, which if accurate, would make the glaucous gull the heaviest gull and shorebird in the world if not (as far as is known) the largest in length on average.<ref>Dementiev, G. P. and N. A. Gladkov. (1951). Ptitsi Sovietskogo Soyuza [Birds of the Soviet Union]. Vol. 2. Israel, in 1968.]: Publishing House Sovietskaya Nauka, Moscow, USSR. [English translation by the Israel Program for Scientific Translations, Jerusalem.</ref><ref name= Weiser>Weiser, Emily and H. Grant Gilchrist. (2012). Glaucous Gull (Larus hyperboreus), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/glagul. DOI: 10.2173/bna.573</ref> These gulls range from Template:Convert in length and can span Template:Convert, with some specimens possibly attaining Template:Convert, across the wings.<ref name=Olsen/><ref name=AAB/><ref name=Harrison/><ref name= Weiser/> Among standard measurements, the wing chord is Template:Convert, the bill is Template:Convert and the tarsus is Template:Convert.<ref name= Olsen/> They take four years to reach maturity.
The call is a "laughing" cry similar to that of the herring gull, but deeper.
Subspecies
The four recognized subspecies are:
| Image | Subspecies | Distribution |
|---|---|---|
| File:Adult Glaucous Gull (Larus hyperboreus), Skaw - geograph.org.uk - 5247885.jpg | L. h. hyperboreus, Gunnerus, 1767 | nominate, found from northern Europe to north-western Siberia |
| File:Glaucous gull (Larus hyperboreus) with offspring, Liefdefjord, Svalbard.jpg | L. h. pallidissimus, Portenko, 1939 | found from north-western Siberia to the Bering Sea - the largest subspecies, paler than hyperboreus with bright raspberry pink legs (possibly due to diet). |
| File:Larus hyperboreus-USFWS.jpg | L. h. barrovianus, Ridgway, 1886 | found from Alaska to north-west Canada - the smallest subspecies, with a darker mantle, shorter bill and longer wings than hyperboreus. First-year immature is generally darker and more strongly-marked than hyperboreus. |
| L. h. leuceretes, Schleep, 1819 | found from north-central Canada to Greenland and Iceland - Averages slightly paler than hyperboreus. Olsen & Larsson (2003) in Gulls of Europe, Asia and North America consider it synonymous with nominate hyperboreus.<ref>Template:Cite book</ref> |
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Ecology
This species of seagull breeds colonially or singly on coasts and cliffs, making a lined nest on the ground or cliff. Normally, two to four light brown eggs with dark brown splotches are laid.
These are omnivores like most Larus gulls, and they eat fish, insects, molluscs, starfish, offal, scraps, eggs, small birds, small mammals, and carrion, as well as seeds, berries, and grains.
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Glaucous gull at De Cocksdorp, Netherlands
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Egg, collection Museum Wiesbaden
