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The Pacific swift (''Apus pacificus'') is a bird which breeds in eastern Asia. This swift is strongly migratory, spending the northern hemisphere's winter in Southeast Asia and Australia. The general shape and blackish plumage recall its relative, the common swift, from which it is distinguished by a white rump band and heavily marked underparts. The sexes are identical in appearance, although young birds can be identified by pale fringes to the wing feathers that are absent in adults. This swift's main call is a screech typical of its family. It is one of a group of closely related Asian swifts formerly regarded as one species. The Pacific swift is found in a wide range of climatic zones and habitats. It breeds in sheltered locations such as caves, natural rock crevices or under the roofs of houses. The nest is a half-cup of dry grass and other fine material that is gathered in flight, cemented with saliva and attached to a vertical surface. The two or three white eggs are incubated for about seventeen days to hatching. Subsequently, the chicks have a long but variable period in the nest before they are fully fledged. When the parents cannot find sufficient food in bad weather, the young can survive for days without being fed by metabolising body fat. Like all members of its family, the Pacific swift feeds exclusively on insects caught in flight. It tends to hunt higher than most of its relatives other than the white-throated needletail. The Pacific swift has a large population and extensive breeding area, and faces few threats from predators or human activities. It is classed as being of least concern by the International Union for Conservation of Nature. It has occurred as far afield as the US and New Zealand, and it is a very rare vagrant in Europe, where it has been recorded in Denmark, Spain, Sweden and the United Kingdom. ==Taxonomy== The swifts form the bird family Apodidae, which is divided into several genera. The Pacific swift is in the Old World genus ''Apus'', which is characterised by dark, glossy plumage, a forked tail and sharply pointed wings.〔Chantler & Driessens (2000) p. 219.〕 Until recently, the Pacific swift was considered to have five subspecies,〔Chantler & Driessens (2000) pp. 235–237.〕 but three have now been elevated to full species status as part of a "fork-tailed swift" superspecies. The proposed name of the superspecies was formerly a synonym for the Pacific swift.〔 A 2011 study proposed the following treatment. The long-tailed birds from the Tibetan Plateau with a narrow white throat patch are separated as Salim Ali's swift, ''A. salimali'', the small swifts with narrow white rumps from the Himalayas of India, Nepal and Bhutan become Blyth's swift, ''A. leuconyx'', and the population that breeds in limestone caves in northern Southeast Asia, characterised by a green iridescence and shallow tail fork, is split as Cook's swift, ''A. cooki''. The remaining subspecies are the nominate ''A. p. pacificus'' and the southern race ''A. p. kurodae'' (which includes the Tibetan population formerly named as ''kanoi'').〔 This arrangement has been accepted by the International Ornithological Committee (IOC), but not the International Union for Conservation of Nature.〔 A 2012 paper showed that ''cooki'' is closely related to the dark-rumped swift, ''A. acuticauda'', which should therefore be included in the ''pacificus'' clade, but made no further taxonomic recommendations. This swift was first described by John Latham in 1801 as ''Hirundo pacifica''.〔Latham (1801) (p. lviii ).〕 Scopoli separated the swifts from the swallows as the genus ''Apus'' in 1777.〔Scopoli (1777) (p. 483 ).〕 ''Apus'', like Apodidae, is derived from the Greek απους, ''apous'', meaning "without feet", a reference to the small, weak legs of these most aerial of birds,〔Jobling (2010) pp. 50–51.〕〔Kaufman (2001) p. 329.〕 and ''pacificus'' refers to the Pacific Ocean.〔Jobling (2010) p. 288.〕 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「Pacific swift」の詳細全文を読む スポンサード リンク
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