Asian white-backed vulture (Gyps bengalensis)

Also known as: white-rumped vulture
  
Spanish: Buitre Dorsiblanco Bengalí, Buitre Leonado Bengalés
KingdomAnimalia
PhylumChordata
ClassAves
OrderFalconiformes
FamilyAccipitridae
GenusGyps (1)
SizeLength: 75 – 85 cm (2)

Classified as Critically Endangered (CR) on the IUCN Red List 2007 (1), and listed on Appendix II of CITES (3).

The Asian white-backed vulture has recently undergone a catastrophic population crash, which threatens the survival of this species. It is a medium-sized vulture (2), with the blunt talons and bare head that characterise this group of carrion-feeding birds (4). The wings are black, whilst the neck-ruff, rump and underwings are white (2). The bare head and neck are black and the bill is silver (2).

Previously abundant throughout southern Asia, the white-backed vulture had all but disappeared from South East Asia by the mid-20th century (2). In contrast, this vulture remained fairly common on the Indian subcontinent until the late 1990s when populations underwent sudden and catastrophic declines throughout the region, prompting the species to be upgraded to Critically Endangered (5).

These vultures are often found close to human habitation, in cities, towns and villages near to cultivation (5). Away from built up areas, vultures are associated with open areas or cultivated fields where there are scattered trees (5).

White-backed vultures are highly social and are found in flocks all year round, often with other species, such as the Indian vulture (Gyps indicus). Groups roost communally at traditional sites (5). Nesting also occurs in groups at traditional sites, nests are situated 2 to 18 metres high and there may be as many as 15 in a single tree (5). The majority of breeding occurs between November and January, females lay a single egg that is then incubated for almost two months. After hatching the chicks remain in the nest for two to three months (5) and their parents feed them by regurgitating food (4).

Vultures feed on carrion, scavenging for carcasses at rubbish dumps, slaughterhouses and in fields (5). They are voracious feeders; a flock of different vulture species has been reported to eat a fresh bullock carcass in just 40 minutes (5). In the Bombay Parsi community, the dead are placed on the ‘Towers of Silence’ on Malabar Hill for the vultures to dispose of (5).

The Asian white-backed vulture was once the commonest vulture in the Indian subcontinent and was abundant throughout its range (4). Populations in South East Asia had all but disappeared by the mid-20th century. These declines have been attributed to direct causes such as hunting and live capture, as well as the indirect effects of a reduction in carrion as hygiene improved across the region (5). Having suffered an extremely rapid decline in numbers due to a previously unknown cause, the Asian white-backed vulture is in danger of imminent extinction without immediate conservation action. By 2000, dead and dying Gyps vultures were being found so frequently in Nepal and India it was thought that they were suffering from an epidemic. The unnaturally high death toll was thought to be caused by a fatal virus, but testing has revealed that vultures are suffering from kidney failure following the consumption of cattle that had previously been treated with the anti-inflammatory drug, diclofenac (2). In fact, the decline is a result of a lethal level of the drug in a small proportion of the ungulate carcasses available to vultures, but as vultures travel long distances to reach carrion, a considerable proportion of the population has been affected (6).

The full extent of the decline of Gyps vulture species is already felt by humans, as rotting carcasses remain untouched, posing a health hazard, as well as encouraging feral dog populations which carry rabies (7).

It is necessary to prevent exposure of vultures to livestock carcasses that have been contaminated with diclofenac, and to find an alternative replacement drug (7). Government commitment to the control of the use of the drug is crucial, but until it has been entirely removed from the environment, a collaboration of bird protection organisations plan to take all Asian white-backed vultures into captivity for the next 20 to 30 years to avoid further deaths, which would further reduce the chance of a successful recovery of this already rare species (7).

For further information on the conservation of vultures see:

Authenticated (20/03/05) by Nick Lindsay, International Zoo Programmes, Zoological Society of London.
http://www.zsl.org

  1. IUCN Red List (August, 2003)
    http://www.iucnredlist.org
  2. BirdLife International (August, 2003)
    http://www.birdlife.org
  3. CITES (August, 2003)
    http://www.cites.org
  4. The Peregrine Fund (August, 2003)
    http://www.peregrinefund.org/
  5. BirdLife International. (2001) Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK.
  6. Green, R.E., Newton, I., Schultz, S., Cunningham, A.A., Gilbert, M., Pain, D.J. and Prakash, V. (2004) Diclofenac poisoning as a cause of vulture population declines across the Indian subcontinent. Journal of Applied Ecology, 41(5): 793 - 800.
  7. National Geographic News (December, 2004)
    http://news.nationalgeographic.com/news/2004/05/0511_040511_vultures.html