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The changeable hawk-eagle or crested hawk-eagle ''(Nisaetus cirrhatus)'' is a bird of prey species of the family Accipitridae. It was formerly placed in the genus ''Spizaetus'', but studies pointed to the group being paraphyletic resulting in the Old World members being placed in ''Nisaetus'' (Hodgson, 1836) and separated from the New World species.〔Helbig AJ, Kocum A, Seibold I & Braun MJ (2005) A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level. Molecular phylogenetics and evolution 35(1):147-164 (PDF )〕 Changeable hawk-eagles breed in the Indian subcontinent, mainly in India and Sri Lanka, and from the southeast rim of the Himalaya across Southeast Asia to Indonesia and the Philippines. This is a bird occurring singly (outside mating season) in open woodland, although island forms prefer a higher tree density. It builds a stick nest in a tree and lays a single egg. ==Description== The changeable hawk-eagle is a medium-large raptor at about in length with a wingspan, and a weight ranging from 1.2 to 1.9 kg.〔http://www.eagledirectory.org/species/crested_hawk_eagle.html〕 It is a relatively slender forest eagle with some subspecies (especially ''N. c. limnaetus'') being dimorphic giving the name "changeable". This and their complicated phylogeny further complicate precise identification. Normally brown above, they have white below with barring on the undersides of the flight feathers and tail; black longitudinal streaks occur on the throat and chocolate streaks occur on the breast. Some subspecies have a crest of four feathers, but this is all but absent in others. The sexes are quite similar in their plumage, but males are about 15% smaller than females.〔Ferguson-Lees & Christie (2001). ''Raptors of the World.'' Christopher Helm, London. ISBN 0713680261〕 The underparts and head of juveniles are whitish or buff with few dark streaks.〔 The wings are long and parallel-sided, and are held flat in flight, which helps to distinguish this species from the similar mountain hawk-eagle. In overhead flight, comparatively rounded wings (upturned at tip), longish tail, white body (spotted with brown) and grey underside of wings (streaked and spotted) are leading pointers. Their call is a loud, high-pitched ''ki-ki-ki-ki-ki-ki-ki-ki-kee'', beginning short, rising in crescendo, and ending in a scream. 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「Changeable hawk-eagle」の詳細全文を読む スポンサード リンク
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