|
The white-throated toucan (''Ramphastos tucanus'') is a near-passerine bird found throughout the Amazon in south-eastern Colombia, eastern Ecuador, eastern Peru, northern Bolivia, southern and eastern Venezuela, northern and western Brazil, including the Amazon Basin's adjacent Tocantins-Araguaia River drainage, and the Guianas. It prefers tropical humid forest, but also occurs in woodland and locally in riverine forest within the Cerrado. It was formerly considered to be two species, with the southern and western nominate subspecies, ''R. t. tucanus'', named the red-billed toucan, and the northern and eastern subspecies, ''R. t. cuvieri'', Cuvier's toucan (when considered a species; ''R. cuvieri, ''Wagler, 1827). However, the two subspecies, which differ principally in the bill colour, interbreed freely wherever they meet and therefore merit only subspecies status. The subspecies ''R. t. inca'' from Bolivia is of questionable validity and may represent a stable hybrid population between ''tucanus'' and ''culminatus''. ==Description== Like other toucans, the white-throated toucan is brightly marked and has a huge bill. It has a total length of 50–61 cm (20–24 in).〔()〕 Body weight is somewhat variable, ranging in adult birds from . The male averages slightly larger, at a mass of , while the female averages . Among standard measurements, the wing chord is , the bill is , the tail is , and the tarsus is . The only species of toucan that surpasses the white-throated in size is the toco toucan. It has black plumage with a white throat and breast bordered below with a narrow red line. The rump is bright yellow and the crissum is red. The bare skin around the eye is blue. The bill has a yellow tip, upper ridge and base of the upper mandible, and the base of the lower mandible is blue. The rest of the bill is mainly black in ''R. t. cuvieri'' and mainly reddish-brown in ''R. t. tucanus'', with intergrades showing a mixed coloration. Males are larger and longer-billed than females, but otherwise the sexes are alike. Juveniles are noticeably shorter-billed, more sooty-black, and have duller plumage. The white-throated toucan of the race ''cuvieri'' is virtually identical to the related channel-billed toucan of the race ''culminatus'', but the latter is smaller and has a proportionally shorter bill with a more strongly keeled culmen. The call is often the best distinction between the species. White-throated has a yelping ''eeoo, hue hue'', whereas channel-billed has a croaking song. 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「White-throated toucan」の詳細全文を読む スポンサード リンク
|