What is causing the crisis?
 Asad Rahmani/BNHS
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Early research suggested a disease, probably a virus, was responsible. Autopsies found the liver and other organs covered with whitish crystals assumed to be uric acid, deposits of which cause gout in humans. Once afflicted, birds seemed unable to recover. A characteristic symptom was drooping of the head, the neck dangling almost as if broken.
The disease appeared to be spreading: by late 2000, the first symptoms were recorded in Pakistan, following the rapid decline of some populations of White-rumped Vultures in Nepal. Researchers feared that a westward spread through Pakistan and on to Europe, the Middle East and Africa was inevitable, with the involvement of another species, Eurasian Griffon G. fulvus, which comes into contact with White rumped Vulture in Pakistan.
Research by the Bombay Natural History Society (BNHS, BirdLife in India) showed most of the affected birds were suffering from acute gout and gut inflammation. Researchers continued to suspect a disease, most likely a virus, but felt this might only be part of the story.
"Since the outbreak of the disease in India, we have witnessed an increase in the number of Eurasian Griffon Vultures spending the winter in India. This species belongs to the same group as those affected and there is every likelihood that Eurasian Griffon Vultures will also be affected." —Dr Andrew Cunningham, Head of Wildlife Epidemiology, ZSL
The three affected species were mostly sedentary, which researchers believed had helped stopped the ‘disease’ spreading to other Gyps species. However, following the beginning of the decline in the three resident species, there was an increase in the number of Eurasian Griffons wintering in India. Concerned that this would put other species of vulture at risk, researchers from BNHS, the RSPB (BirdLife in the UK) and the Zoological Society of London began a programme of satellite tracking to monitor Eurasian Griffon movements. The three partners also set up a Vulture Care Centre in Haryana State, India.
In May 2003, at a meeting of raptor biologists, a scientist working with The Peregrine Fund, presented information on the deaths of vultures from three colonies in Pakistan, which opened up a new possibility. Birds with gout had high levels of an anti-inflammatory painkilling drug (diclofenac) in their kidneys, while birds that had not died from gout had undetectable levels.