Lesser Yellow-headed Vulture

识别特征

This is the lightest and smallest of the extant New World vultures despite sometimes measuring at least as long and longer winged than black vultures. The lesser yellow-headed vulture is 53–66 cm (21–26 in) in length, with a wingspan of 150–165 cm (59–65 in) and a tail length of 19–24 cm (7.5–9.4 in). Its weight ranges from 0.95 to 1.55 kg (2.1 to 3.4 lb). Its plumage is black with a green sheen. The throat and the sides of the head are featherless. The head and neck are bare of feathers, and the skin is yellow, with a reddish forehead and nape and a gray-blue crown. The irises of its eyes are red, its legs are white, and its beak is flesh-colored. The eye has a single incomplete row of eyelashes on the upper lid and two rows on the lower lid.The tail is rounded and relatively short for a vulture; the tip of the closed wing extends beyond the tail. Immature lesser yellow-headed vultures have browner plumage, a dusky head, and a white nape.<p>The beak is thick, rounded, and hooked at the tip.The front toes are long with small webs at their bases and are not adapted to grasping. The opening of the nostril is longitudinal, and the nostrils lack a septum. Like all New World vultures, the lesser yellow-headed vulture lacks a syrinx, and is therefore unable to make any sound other than a low hiss.<p>It differs in appearance from the similar greater yellow-headed vulture in several ways. It is smaller and is less heavily built than the greater yellow-headed vulture and has a shorter, thinner tail. The plumage is browner than the greater yellow-headed vulture's dark, glossy black plumage. Its legs are lighter in color, and its head is more orange-tinged than the more yellow head of the greater yellow-headed vulture. Its flight is also less steady than that of the greater yellow-headed vulture. The lesser yellow-headed vulture also prefers to live in savannas, as opposed to the preferred forest habitat of the greater yellow-headed vulture.<p>Besides the greater yellow-headed vulture, it is similar to the turkey vulture.

分类信息

The lesser yellow-headed vulture was first described in 1845 by John Cassin. It is sometimes recognized as having two subspecies. The first, Cathartes burrovianus urubitinga, described by Austrian ornithologist August von Pelzeln in 1851, is the larger of the two and is found from Argentina north to Colombia, while the nominate subspecies, Cathartes burrovianus burrovianus, is smaller and found from northwestern South America through Central America to Mexico. The lesser yellow-headed vulture's genus, Cathartes, means "purifier" and is from the Latinized form of the Greek kathartēs/καθαρτης. The common name, vulture, is derived from the Latin word vulturus, which means "tearer" and is a reference to its feeding habits.<p>The exact taxonomic placement of the lesser yellow-headed vulture and the remaining six species of New World vultures remains unclear. Although both are similar in appearance and have similar ecological roles, the New World and Old World vultures evolved from different ancestors in different parts of the world. Just how different the two are is currently under debate, with some earlier authorities suggesting that the New World vultures are more closely related to storks. More recent authorities maintain their overall position in the order Falconiformes along with the Old World vultures or place them in their own order, Cathartiformes. The South American Classification Committee has removed the New World vultures from Ciconiiformes and instead placed them in Incertae sedis, but notes that a move to Falconiformes or Cathartiformes is possible. Like other New World vultures, the lesser yellow-headed vulture has a diploid chromosome number of 80.

学名

Cathartes burrovianus

命名信息

Cassin, 1845

目

Cathartiformes

科

Cathartidae

属

Cathartes

分布与栖息地

It is found in Argentina, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela.Its natural habitats are subtropical or tropical seasonally wet or flooded lowland grassland, swamps, mangroves, and heavily degraded former forest. It may wander over dry fields and clearings. It is not generally found in high-altitude regions.<p>This bird with its somehow crow-like aspect gave foot to the naming of the Quebrada de los Cuervos (Crows Ravine) in Uruguay, where they dwell together with the black vulture and the turkey vulture.

迁徙

Resident species

行为

Migration pattern: Resident species.

保护状况

Population trend: stable.

种群趋势

stable