Home

News

Background

History of declines

Threatened vultures

Vulture research

Breeding centres

Advocacy programme

Publications

Press

Partners & People

Project funding and support

Related links

Contact

History of declines

The vulture declines in India were first recorded in Keoladeo National Park, Rajasthan, by Dr. Vibhu Prakash, principal scientist of the Bombay Natural History Society. Between 1985-1986 and 1996-1997 the population size of Oriental white-backed vultures declined by an estimated 97% at Keoladeo, and in 2003 this colony was extinct. These declines were coupled with high mortality of all age classes. Since the initial surveys, BNHS teams have confirmed that these declines have occurred in all regions across India. Some birds appear sick and lethargic for a protracted period before death, often exhibiting a 'neck drooping' posture, characteristic of a vulture that is weak and dehydrated.

Causes of declines

Following the identification of the declines, a number of hypotheses were proposed about the possible causes, including contaminants, infectious disease and food shortage. The geographical pattern, extent and spread of declines, along with results from analyses of blood from sick birds, and tissues from dead birds in India, initially suggested infectious disease as a likely cause of the declines. However, research by The Peregrine Fund in Pakistan discovered that the major cause of the population decline was diclofenac, an non steroidal anti-inflammatory drug (NSAID) used widely in veterinary medicine across South Asia (Oaks et al. 2004, which can be accessed from this web page of The Peregrine Fund). Research by Vulture Rescue has confirmed that diclofenac is the cause of vulture declines across the rest of the Indian subcontinent (Shultz et al. 2004), and population modelling has shown that less than 1% of carcasses need to contain a lethal quantity of diclofenac for this drug to be the main, or only, cause of the decline in vulture numbers (Green et al. 2004).

The vulture declines have wide reaching impacts on humans and other animals in Asia

Click here for more information