| 词条 | White-throated toucan |
| 释义 |
| name = White-throated toucan | status = VU | status_system = IUCN3.1 | status_ref = [1] | image = Red-billed toucan 31l07.JPG | image_caption = Ramphastos t. tucanus | genus = Ramphastos | species = tucanus | authority = Linnaeus, 1758 | subdivision_ranks = Subspecies | subdivision = See text | synonyms = * Ramphastos Tucanus }} The white-throated toucan (Ramphastos tucanus) is a near-passerine bird in the family Ramphastidae found in South America throughout the Amazon Basin including the adjacent Tocantins and Araguaia River drainage. It prefers tropical humid forest, but also occurs in woodland and locally in riverine forest within the Cerrado. This bird can be found in Bolivia in the Beni Departement, notably in the city of Riberalta and in the closeby Aquicuana Reserve. Taxonomy and systematicsThe white-throated toucan was formerly considered to be three separate species. The red-billed toucan and Cuvier's toucan, which differ principally in the bill colour, interbreed freely wherever they meet and therefore now merit only subspecies status. Some authorities consider the Inca toucan to represent a stable hybrid population between the other two subspecies and do not recognize it as a separate subspecies. SubspeciesThree subspecies are recognized:[2]
DescriptionLike other toucans, the white-throated toucan is brightly marked and has a huge bill. It has a total length of {{convert|50|–|61|cm|in|round=0.5|abbr=on}}.[3] Body weight is somewhat variable, ranging in adult birds from {{convert|425|to|830|g|lb|abbr=on}}. The male averages slightly larger, at a mass of {{convert|642|g|lb|abbr=on}}, while the female averages {{convert|580|g|lb|abbr=on}}. Among standard measurements, the wing chord is {{convert|20.4|to|26.5|cm|in|abbr=on}}, the bill is {{convert|12.2|to|22|cm|in|abbr=on}}, the tail is {{convert|13.3|to|16.8|cm|in|abbr=on}}, and the tarsus is {{convert|4.5|to|5.6|cm|in|abbr=on}}.[4] 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 (the area around the cloaca) 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. BehaviourSmall flocks or more commonly pairs of birds move through the forest with a heavy, rather weak, undulating flight, rarely flying more than {{convert|100|m|ft|abbr=on}} at a time. This species is primarily an arboreal fruit-eater, but will also take insects, lizards, eggs, and small birds. BreedingThe 2–4 white eggs are laid in an unlined cavity high in a decayed section of a living tree, or in an old woodpecker nest in a dead tree. Both sexes incubate the eggs for at 14–15 days, and the toucan chicks remain in the nest after hatching. They are blind and naked at birth, with short bills, and have specialised pads on their heels to protect them from the rough floor of the nest. They are fed by both parents, and fledge after about 6 weeks. The parents continue feeding the juveniles for several weeks after they have left the nest. References
1. ^{{IUCN|id=22735244 |title=Ramphastos tucanus |assessor=BirdLife International |assessor-link=BirdLife International |version=2013.2 |year=2012 |accessdate=26 November 2013}} 2. ^{{Cite journal|title=IOC World Bird List 6.4|url=http://www.worldbirdnames.org/ioc-lists/crossref|journal=IOC World Bird List Datasets|doi=10.14344/ioc.ml.6.4}} 3. ^ 4. ^{{cite book| author = Lester Short|author2=Jennifer F. M. Horne| title = Toucans, Barbets, and Honeyguides: Ramphastidae, Capitonidae and Indicatoridae| year = 2001| publisher = Oxford University Press| isbn = 978-0-19-854666-5}} External links{{Commons category|Ramphastos tucanus}}
Bibliography
5 : Ramphastos|Birds of the Amazon Basin|Birds of the Guianas|Birds described in 1758|Birds of Brazil |
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