Flight to extinction

IUCN lists three species of Indian vultures as critically endangered

Published: Friday 15 November 2002

-- (Credit: Amit Shanker / CSE)the dramatic decline of the vulture population in India has now got official recognition from the World Conservation Union (iucn). It has upgraded three species of Indian vulture on to the critically endangered list. The white-backed vulture (Gyps bengalensis) long-billed vulture (Gyps indicus) and the slender-billed vulture (Gyps tenuirostris), says the iucn, have suffered extremely rapid population declines, particularly across the Indian subcontinent, as a result of disease, poisoning, pesticide use and changes in the processing of dead livestock.

The iucn red list system, using numerous criteria and field studies, categorises animals or plant species into eight categories, ranging from extinct to those at low risk. A species is classified as critically endangered if, among other reasons, its population reduces by more than 90 per cent over three generations.

With a great amount of ornithological interest being shown in vultures, many studies in the past have recorded the plight of the bald warriors. In some parts of the country their population has declined by more than 95 per cent. For instance, in Rajasthan's Keoladeo National Park, it was found that the vulture population had reduced from 1,800 in 1986 to 86 in 1999. No white-rumped vulture was recorded in the park in 2000. Vibhu Prakash, an expert on vultures working for Bombay Natural History Society, Mumbai, records, "In a number of places, including the protected areas, there has been a complete wipe out of these birds."

In total, eight species of vultures inhabit India. Other than the three listed as critically endangered, populations of the Himalayan griffon (Gyps himalayensis), the king vulture (Sarcogypus calvus) the Cinerious vulture (Aegypius monachus) and the Egyptian vulture (Neophron pernopterus) are also reportedly declining.
What's killing the grim reaper? The cause of the vultures' death in India has become a contentious issue in ornithological circles. Some blame the growing use of toxic substances and pesticides in agriculture, as is the case of the bald eagle in the us. The other set of experts think a virulent infection is to be blamed. The infection caused by the adinovirus leads to no outward symptoms other than the drooping of the affected bird's head. The bird dies within a month of being infected. According to Munir Virani, of the us-based Peregrine Fund, the infectious disease factor is believed to have originated in South Asia and travelled west to India.

In fact, recently researchers from the Britain-based Royal Society for the Protection of Birds (rspb) have expressed fears that the viral disease, which has already spread to Nepal and Pakistan, could wipe out the vulture populations of Europe and Africa. They claim, this will happen due to the arrival of foreign vultures in India. These are, they propound, attracted by the huge numbers of infected cattle carcasses lying in waste dumps across the country. "This year, we have seen thousands of migrating Eurasian vultures at a big dump in eastern India," says Deborah Pain of rspb. "They could easily and rapidly transmit the viral disease to Europe and Africa. Vulture populations of France, Spain and African bush are particularly susceptible," says Pain. "This will have massive ecological impacts."

However, there are conflicting opinions about this hypothesis. Indian scientists like S M Satheesan, a Mumbai-based consulting ornithologist, do not agree. Satheesan believes that such claims are being made to secure funding to conduct projects in India. According to him, most of the vulture populations in India were decimated by denying carcasses to them and shooting them down because they were turning into an aviation hazard since the 1980s. They were also trapped and poisoned for various reasons, he says. High vulture mortality is also attributed to large-scale indirect poisoning by poachers, cattle rustlers and villagers, and trapping of these birds for various purposes (see: 'What's eating the vulture?', Down To Earth, Vol 7, No 16, January 15, 1999).

According to Satheesan, the species could be prevented from becoming extinct by providing food and safety. Moreover, if a disease is one of the factors causing their decline, then it is vital to find out its pathogen, invent vaccine and inoculate it to wild vulture populations.

Another way out, according to some, is captive breeding. "A healthy captive population may be the only hope of keeping the birds going," says Peter Wood, an ornithologist with rspb. According to him, these birds can be first studied for the reasons of decline and then eventually be used to repopulate the wild.

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