Concept

Stercorariidae

Résumé
The skuas ˈskjuːə are a group of predatory seabirds with seven species forming the genus Stercorarius, the only genus in the family Stercorariidae. The three smaller skuas, the Arctic skua, the long-tailed skua, and the pomarine skua, are called jaegers in North American English. The English word "skua" comes from the Faroese name for the great skua, skúgvur ˈskɪkvʊɹ, with the island of Skúvoy renowned for its colony of that bird. The general Faroese term for skuas is kjógvi ˈtʃɛkvɪ. The word "jaeger" is derived from the German word Jäger, meaning "hunter". The genus name Stercorarius is Latin and means "of dung"; the food disgorged by other birds when pursued by skuas was once thought to be excrement. Skuas nest on the ground in temperate and Arctic regions, and are long-distance migrants. They have even been sighted at the South Pole. Outside the breeding season, skuas take fish, offal, and carrion. Many practice kleptoparasitism, which comprises up to 95% of the feeding methods of wintering skuas, by chasing gulls, terns and other seabirds to steal their catches, regardless of the size of the species attacked (up to three 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 seen killing birds as large as a grey heron. 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 chicks of other seabirds, primarily penguins, 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 carcasses at breeding colonies of both penguins and pinnipeds. Skuas will also kill live penguin chicks. In these areas, the skuas will often forfeit their catches to the considerably larger and very aggressive giant petrels.
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