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The Pallas's gull or great black-headed gull (''Ichthyaetus ichthyaetus'') is a large gull. As is the case with many gulls, it has traditionally been placed in the genus ''Larus''.〔Pons J.M., Hassanin, A., and Crochet P.A.(2005). ''Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers.'' Molecular phylogenetics and evolution 37(3):686-699〕 This species breeds in colonies in marshes and islands from southern Russia to Mongolia. It is migratory, wintering in the eastern Mediterranean, Arabia and India. This gull nests on the ground, laying between two and four eggs. It occurs in western Europe only as a rare vagrant. In Great Britain a recent review left a single occurrence in 1859 as the only acceptable record of this bird. The species also occurs as a vagrant in differing parts of the Indian Ocean, south of its normal range, and along the northern and eastern coasts of Africa, where it visits annually on an irregular basis.〔''Field Guide to the Birds of East Africa: Kenya, Tanzania, Uganda, Rwanda, Burundi'' by Stevenson & Fanshawe. Elsevier Science (2001), ISBN 978-0856610790〕 This is a very large gull, being easily the world's largest black-headed gull and the third largest species of gull in the world, after the great black-backed gull and the glaucous gull. It measures in length with a wingspan.〔''Gulls: Of North America, Europe, and Asia'' by Klaus Malling Olsen & Hans Larsson. Princeton University Press (2004). ISBN 978-0691119977.〕〔Harrison, Peter, ''Seabirds: An Identification Guide''. Houghton Mifflin Harcourt (1991), ISBN 978-0-395-60291-1〕 Weight can vary from , with an average of in males and in females.〔''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.〕 Among standard measurements, the wing chord is , the bill is and the tarsus is .〔 Summer adults are unmistakable, since no other gull of this size has a black hood. The adults have grey wings and back, with conspicuous white "mirrors" at the wing tips. The legs are yellow and the bill is red. In all other plumages, a dark mask through the eye indicates the vestiges of the hood. The call is a deep ''aargh'' cry. Young birds attain largely grey upperparts quite rapidly, but they take four years to reach maturity. These birds are predatory, taking fish, crustaceans, insects and even small mammals. The Pallas's gull is one of the species to which the ''Agreement on the Conservation of African-Eurasian Migratory Waterbirds'' (AEWA) applies. This bird has a deep, rather nasal flight-call which resembles the call of the lesser black-backed gull. Although they are noisy at colonies, Pallas's gulls are mostly silent when breeding. ==References== == Gallery == File:Pallas's Gull (Larus ichthyaetus) W IMG 6954.jpg|In flight Krishna Wildlife Sanctuary, Andhra Pradesh, India. File:Larus ichtyaetus 3.png|AdultManych River, Kalmykia, Russia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pallas's gull」の詳細全文を読む スポンサード リンク
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