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The skuas are a group of seabirds with about seven species forming the family Stercorariidae and the genus ''Stercorarius''. The three smaller skuas are called jaegers in the Americas. The English word "skua" comes from the Faroese name ''skúgvur'' (:ˈskɪkvʊər) for the great skua, with the island of Skúvoy renowned for its colony of that bird. The general Faroese term for skuas is ''kjógvi'' (:ˈtʃɛkvə). The word "jaeger" is derived from the German word ''Jäger'', meaning "hunter". Skuas nest on the ground in temperate and Arctic regions, and are long-distance migrants. They have even been sighted at the South Pole.〔Mark Sabbatini, ("Non-human life form seen at Pole" ), ''The Antarctic Sun'', 5 January 2003.〕 ==Biology and habits== Outside the breeding season, skuas take fish, offal, and carrion. Many are partial kleptoparasites, comprising up to 95% of the feeding methods of wintering birds, by chasing gulls, terns and other seabirds to steal their catches, regardless of the size of the species attacked (up to 3 times heavier than the attacking skua). The larger species, such as the great skua, also regularly kill and eat adult birds, such as puffins and gulls, and have been recorded as killing birds as large as a grey heron.〔(Scottish Ornithologists' Club )〕 On the breeding grounds, the three, more slender northern breeding species commonly eat lemmings. Those species that breed in the southern oceans, largely feed on fish that can be caught near their colonies. The eggs and young of other birds are an important food source for most skua species during the nesting season. In the southern oceans and Antarctica region, some skua species (especially the south polar skua) will readily scavenge the carcasses at breeding colonies of penguins and pinnipeds, sometimes taking live penguin chicks. In these areas, skuas seem to defer to the considerably larger giant petrels.〔http://carnivoraforum.com/index.cgi?board=interspecific&action=print&thread=390〕 They are medium to large birds, typically with grey or brown plumage, often with white markings on the wings.〔 The skuas range in size from the long-tailed skua, ''Stercorarius longicauda'', at , to the brown skua, ''Stercorarius antarcticus'', at . On average, a skua is about long, and across the wings. They have longish bills with a hooked tip, and webbed feet with sharp claws. They look like large dark gulls, but have a fleshy cere above the upper mandible. The skuas are strong, acrobatic fliers. They are generally aggressive in disposition. Potential predators who go near their nest will be quickly dived at by the parent bird, which usually targets the head of the intruder - a practice known as 'dive bombing'. 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「skua」の詳細全文を読む スポンサード リンク
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