The white-rumped vulture (Gyps bengalensis) is an Old World vulture native to South and Southeast Asia. It has been listed as Critically Endangered on the IUCN Red List since 2000, as the population severely declined. White-rumped vultures are threatened by diclofenac poisoning, which kills them by causing kidney failure.

It is closely related to the European griffon vulture (Gyps fulvus). At one time it was believed to be closer to the white-backed vulture of Africa and was known as the Oriental white-backed vulture.

Gmelin based his description on the "Bengal vulture" that had been described and illustrated in 1781 by the English ornithologist John Latham in his multi-volume A General Synopsis of Birds. Latham had seen a live bird at the Tower of London and had been told by the keeper that it had come from Bengal.

The white-rumped vulture is now one of eight species placed in the genus Gyps that was introduced in 1809 by the French zoologist Marie Jules César Savigny. The genus name is from Ancient Greek gups meaning "vultur". The species is monotypic: no subspecies are recognised.

Description

thumb|Showing wings, in Chitwan National Park, Nepal

thumb|In [[Bangladesh]]

The white-rumped vulture is the smallest of the Gyps vultures, but is still a very large bird. It weighs , measures in length,

It has an unfeathered head and neck, very broad wings, and short tail feathers. It is much smaller than the Eurasian Griffon. It has a white neck ruff. The adult's whitish back, rump, and underwing coverts contrast with the otherwise dark plumage. The body is black and the secondaries are silvery grey. The head is tinged in pink and bill is silvery with dark ceres. The nostril openings are slit-like. Juveniles are largely dark and take about four or five years to acquire the adult plumage. In flight, the adults show a dark leading edge of the wing and has a white wing-lining on the underside. The undertail coverts are black. It often flies and sits in flocks. At one time, it was the most numerous vulture in India.

White-rumped vultures usually become active when the morning sun is warming up the air so that thermals are sufficient to support their soaring. They were once visible above Calcutta in large numbers.thumb|Fighting over a carcass, in NepalWhen they find a carcass, they quickly descend and feed voraciously. They perch on trees nearby and are known to sometimes descend also after dark to feed. At kill sites, they are dominated by red-headed vultures Sarcogyps calvus.

In forests, their soaring often indicated a tiger kill.

Where water is available they bathe regularly and also drink water. A pack of vultures was observed to have cleaned up a whole bullock in about 20 minutes. Trees on which they regularly roost are often white from their excreta, and this acidity often kills the trees. This made them less welcome in orchards and plantations.

They sometimes feed on dead vultures. One white-rumped vulture was observed when getting caught in the mouth of a dying calf.thumb|Underwing pattern of an adult, in [[Assam, India]]Solitary nests are not used regularly and are sometimes taken over by the red-headed vulture and large owls such as Bubo coromandus. The male initially brings twigs and arranges them to form the nest. During courtship the male bills the female's head, back and neck. The female invites copulation, and the male mounts and hold the head of the female in his bill.

A captive individual lived for at least 12 years.

Status and decline

In the Indian subcontinent

thumb|White-rumped vulture in [[Desert National Park, India]]

thumb|A pair of white-rumped vultures in [[Maharashtra, India]]

The white-rumped vulture was originally very common especially in the Gangetic plains of India, and often seen nesting on the avenue trees within large cities in the region. Hugh Whistler noted for instance in his guide to the birds of India that it "is the commonest of all the vultures of India, and must be familiar to those who have visited the Towers of Silence in Bombay."

Before the 1990s they were even seen as a nuisance, particularly to aircraft as they were often involved in bird strikes. In 1941 Charles McCann wrote about the death of Borassus palms due to the effect of excreta from vultures roosting on them. In 1990, the species had already become rare in Andhra Pradesh in the districts of Guntur and Prakasham. The hunting of the birds for meat by the Bandola (Banda) people there was attributed as a reason. A cyclone in the region during 1990 resulted in numerous livestock deaths and no vultures were found at the carcasses.

This species, as well as the Indian vulture and slender-billed vulture has suffered a 99% population decrease in India and nearby countries since the early 1990s. The decline has been widely attributed to poisoning by diclofenac, which is used as veterinary non-steroidal anti-inflammatory drug (NSAID), leaving traces in cattle carcasses which when fed on leads to kidney failure in birds. Other NSAIDs were also found to be toxic, to Gyps as well as other birds such as storks. These pesticide levels have not however been implicated in the decline. Yet another suggestion has been that the population changes may be linked with long term climatic cycles such as the El Niño–Southern Oscillation.

Affected vultures were initially reported to adopt a drooped neck posture and this was considered a symptom of pesticide poisoning,

Other sources

  • Ahmad, S. 2004. Time activity budget of Oriental White-backed Vulture (Gyps bengalensis) in Punjab, Pakistan. M. Phil. thesis, Bahauddin Zakariya University, Multan, Pakistan.
  • Grubh, R. B. 1974. The ecology and behaviour of vultures in Gir Forest. Ph.D. dissertation, University of Bombay, Bombay, India.
  • Grubh, R. B. 1988. A comparative study of the ecology and distribution of the Indian White-backed Vulture (Gyps bengalensis) and the Long-billed Vulture (G. indicus) in the Indian region. Pages 2763–2767 in Acta 19 Congressus Internationalis Ornithologici. Volume 2. Ottawa, Canada 22–29 June 1986 (H. Ouellet, Ed.). University of Ottawa Press, Ottawa, Ontario.
  • Eck, S. 1981. [Thanatose beim Bengalgeier (Gyps bengalensis)]. Ornithologische Jahresberichte des Museums Heineanum 5-6:71-73.
  • Naidoo, Vinasan 2008. Diclofenac in Gyps vultures : a molecular mechanism of toxicity. Ph.D. Thesis, University of Pretoria. Fulltext (Includes old photos showing their numbers)
  • Vulture Territory Facts and Characteristics: Asian white-backed vulture
  • BirdLife Species Factsheet
  • media on Arkive
  • Indian white-backed vulture media on the Internet Bird Collection