White-backed vulture
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White-backed vulture ( Gyps africanus ) |
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| Salvadori , 1865 |
The white-backed vulture ( Gyps africanus ) is a bird of prey from the subfamily of the Old World vultures (Aegypiinae). The range of the species covers large parts of Africa south of the Sahara . Due to strong population declines in parts of the distribution area, the IUCN classifies the white-backed vulture as a species on the Red List ("critically endangered").
description
White-backed vultures are medium-sized Old World vultures with long wings and a short and only slightly rounded tail. The wings of the hand are fingered deep. The arm wings are longer than the inner hand wings, so the trailing edge of the wing is curved and not straight. The species shows no sexual dimorphism in terms of color, size or weight. The body length is 78–90 cm, the wingspan 197–229 cm, the weight 4.2–7.2 kg and the wing length 550–640 mm.
This vulture is generally brownish in color, but shows white plumage. The largest part of the trunk, the leg fletching as well as the small and middle upper wing coverts are pale brown to light reddish brown in adult birds with distinct light beige dots on the underside of the trunk. In very old birds, these plumage areas can be almost creamy white. In contrast, the large upper and lower wing covers, the wings and the control feathers are almost monochrome black-brown. The lower back, rump, and the small and medium-sized coverts are white. The skin of the head and neck is black and more or less sparsely whitish or cream-colored. These downs are densest on the skull and neck and are largely absent on the face and front neck. The loose, densely downy ruff is white. The rather long and strong beak, the wax skin , the featherless parts of the legs and the toes are blackish gray.
Young birds are significantly darker than adults. When young, the entire trunk including the rump as well as the small and middle upper and lower wing coverts are dark brown with narrow whitish dots. The ruff consists of narrow, lanceolate, light brown feathers. The head and neck are more densely colored, the bare skin of the face is greenish black. White-backed vultures are colored between 6 and 7 years of age.
distribution and habitat
The distribution area covers large parts of Africa south of the Sahara. It stretches in an east-west direction from Senegal to Somalia , in a north-south direction from south Mali and east Sudan, with the exception of the central African rainforest, to northern South Africa .
The species inhabits a broad spectrum of open and tree-lined landscapes, from open grasslands, savannahs and open swamps to sparsely forested areas, trees and thorn bush vegetation that accompany rivers. It is absent in dense tree-lined landscapes and in closed forests. These vultures are most common where larger mammals are also common for food, and also show a close bond with cattle ranches and ranching nomads, but avoid villages and towns. White-backed vultures occur predominantly from sea level to 1500 m, in Kenya also up to 3000 m and in Ethiopia even up to 3500 m.
nutrition
As with other species of the genus Gyps, the food probably consists exclusively of carrion , especially of large mammals. The animals mainly eat the innards and the softer meat.
Foraging begins two to three hours after sunrise. White-backed vultures circling in the thermal up to heights of 200 to 500 m and then observe other carrion or live animals eating birds and mammals. The cap vultures, which often meet first on the carrion, and especially immature jugglers , then quickly attract a large number of white-backed vultures. The species is usually the most common vulture on the carrion, several dozen or even several hundred white-backed vultures can gather on a single carrion. Smaller mammals like impalas can then be completely consumed in less than 10 minutes. The species is not strong enough to tear open thick skin; the slender beak, the narrow head and the long neck are very well suited to penetrate deep into the animal body through openings of any kind or wounds.
Reproduction
The species occasionally breeds singly, but mostly in loose colonies of 5–20 pairs in neighboring trees; occasionally several pairs breed in the same tree. The breeding season varies depending on the geographical distribution. In northern Africa it falls mainly in the period from October to June, in southeast and South Africa mainly in April / May to December or January and is year-round in Uganda and Kenya, which are close to the equator. The relatively small, 34–100 cm wide and 10–90 cm high nest is built at a height of 5 to 50 m on the crown of a large tree. It is made of branches and is padded with grass and green leaves. The one to three eggs are incubated for 56-58 days. The nestling period lasts 120–130 days.
Existence and endangerment
The species is the most common vulture in sub-Saharan Africa, the world population was estimated at 270,000 individuals in the early 1990s. In western Africa, however, like other vultures, the population has collapsed by over 90%. The population is also declining in Sudan and Kenya. In Ethiopia, Tanzania and southern Africa the stocks are apparently still stable.
The main causes of the decline are habitat destruction as a result of agricultural use, the reduction in the population of large mammals, human persecution and collisions with power lines. The IUCN now classifies the white-backed vulture as a species on the Red List ("critically endangered").
literature
- James Ferguson-Lees , David A. Christie: Raptors of the World. Christopher Helm, London 2001, ISBN 0-7136-8026-1 , pp. 122-123 and 425-426.
Individual evidence
- ^ J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London 2001, pp. 122 and 426.
- ^ J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London 2001, p. 426.
Web links
- Videos, photos and sound recordings on Gyps africanus in the Internet Bird Collection
- Gyps africanus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on January 17 of 2009.