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The common pochard (''Aythya ferina'') is a medium-sized diving duck. The adult male has a long dark bill with a grey band, a red head and neck, a black breast, red eyes and a grey back. The adult female has a brown head and body and a narrower grey bill-band. The triangular head shape is distinctive. Pochards are superficially similar to the closely related North American redhead and canvasback. Females give hoarse growls. Males have whistles cut off by a final nasal note ''aaoo-oo-haa''. Their breeding habitat consists of marshes and lakes with a metre or more water depth. Pochards breed in much of temperate and northern Europe into Asia. They are migratory, and spend winter in the southern and west of Europe. These are gregarious birds, forming large flocks in winter, often mixed with other diving ducks such as the tufted duck, with which they are known to hybridise. These birds feed mainly by diving or dabbling. They eat aquatic plants with some molluscs, aquatic insects and small fish. They often feed at night, and will up-end for food as well as the more characteristic diving. In the British Isles, birds breed in eastern England and lowland Scotland, in small numbers in Northern Ireland with numbers increasing gradually, and sporadically in the Republic of Ireland, where it may also be increasing. Large numbers stay overwinter in Great Britain, after the birds retreat from Russia and Scandinavia. The pochard is one of the species to which the ''Agreement on the Conservation of African-Eurasian Migratory Waterbirds'' (AEWA) applies. ==References== 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「Common pochard」の詳細全文を読む スポンサード リンク
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