Until three or four years ago, large, ferocious-looking vultures were to be seen on top of most of the large Moghul tombs scattered around India’s capital city of New Delhi, perched as though carved in stone. Elsewhere these greyish-brown birds would be in trees, searching through the polluted air for dead carcasses to ravage – 40,000 cows, regarded as sacred in India’s main Hindu religion, live (and die) on the city’s streets. Now the vultures are nowhere to be seen.
It would be tempting to assume that even these scavengers have been driven out of what was once the pride of the British Raj but is now the world’s fourth most polluted city, with winter-time smog reminiscent of London’s yellowish skies of the 1950s.
But the vultures have not only left Delhi: they are declining in most parts of India, where for centuries they have been one of the commonest sights. No one is sure how many there used to be, nor the rate of decline – and the reasons for their sudden rapid disappearance are baffling experts.
What is certain, though, is that their absence poses serious health hazards for a developing country such as India with its chronically low levels of public hygiene and health care. Some scientists believe that the vultures could be facing extinction and describe this as symptomatic of what is happening to the environment.
“Vultures are important ecologically,” says Dr Asad Rahmani, director of the Bombay Natural History Society and one of India’s top ornithologists. “They remove the carcasses of dead animals which otherwise are not cleaned up but are left lying around rotting – thus increasing the risk of spreading disease.”
Vultures are usually described as birds of prey, though the species that occur in India are mostly carrion eaters. They have wingspans of up to two metres, and their keen eyesight and sense of smell enable them to find food. They can demolish rotting carcasses with astonishing speed and efficiency. An army of 200 vultures can reduce a buffalo carcass to bare bones within 20 minutes. The bones are left so clean that they are often collected by villagers and sold to processing factories for about five rupees (3fp) a kilo.
Statistics are hard to come by – vultures are not popular subjects for academic researchers, nor for wildlife conservationists, who generally focus on more glamorous endangered species such as tigers and elephants. The most graphic figures come from the Keoladeo Ghana national park at Bharatpur, an important 11-square-mile bird sanctuary which is a popular tourist spot on the road between the Taj Mahal at Agra and the Rajasthan city of Jaipur. The number of vultures in the sanctuary has plummeted from about 2,000 in 1986 to just eight this year.
Villagers were the first to spot the vultures’ disappearance in the mid-1990s, and there are now reports of decline – and a corresponding increase in rotting carcasses – from across the country. Rahmani says he recently saw nine uneaten carcasses on the 160-mile road between Jaipur and Delhi, and as many as 100 carcasses have been counted at Bharatpur – none of them being eaten by vultures. Earlier there would have been a few vultures on each carcass.
Messages on the Internet show that this is not just a problem in India. Experts have filed reports from South Africa, Latin America and the US, as well as elsewhere in Asia. Even Sanctuary, a (British) Ministry of Defence magazine, had an article last year from Cyprus reporting that griffon vultures had declined from “hundreds” 50 years ago to about 100 in the 1980s and just 24 last year. But scientists in these far-flung countries seem to have no better idea about the precise source of the problem than those in India.
“It could be pesticides, or general pollution, or some poisoning or disease, or a combination of them all,” says Rahmani. “My hunch is pesticides, but we have not yet got a detailed study to provide us with concrete evidence.”
Pesticides could be working through the bodies of dead cows, buffalos and other carcasses eaten by vultures (and by other birds). As a result, vultures’ eggs would have thin, weak shells that break during incubation before the chicks can form and hatch; no vulture chicks have hatched at Bharatpur for the past two years. Adult birds are also falling sick, presumably diseased (maybe with an unknown virus) or poisoned. They have been seen slowly collapsing and dying – sometimes by the waterholes where they would normally be eating carcasses.
Pesticides have been blamed internationally for killing off bird populations for 30 years or more. The Smithsonian Migratory Bird Centre of the US says that “population decline and extensive mortality of birds strongly indicate that the health of the environment, and thus the health of organisms that depend on it, suffers due to the prevalence of pesticides”.
A small sample survey of eight cattle and pig carcasses collected last December in Delhi, Bharatpur and other north Indian locations by the Delhi-based Council for Science and Environment found high levels of pesticides, including DDT, which, although banned in agriculture, is still widely used in India. (It has also been banned in the US, which continues to export it to India and other countries.)
Pesticides are a specially sensitive issue in India. They have caused serious damage to Indian cotton in the past couple of years, which led early last year to more than 300 suicides by cotton farmers who lost their crops and their livelihoods. The US Food and Drug Agency was reported recently to have listed more than 40 Indian companies for exporting papadams, pickles, basmati rice and other food with illegal pesticide residues.
But the pesticide lobby has great influence in India, and vulture experts steer away from blaming them, preferring to emphasise other possible causes of the decline. They cite lack of food (because carcasses are disposed of more efficiently in some urban areas); vultures being killed by villagers who see them as predators on their animals; and indirect poisoning through baits laid for other predators. “Quack” doctors are also said to pay as much as 3,000 rupees (about £50, a fortune for many Indians) for dead vultures that they use in their remedies.
However, most leading experts dismiss these causes as marginal. Dr Vibhu Prakash, India’s leading field researcher on the subject, suspects that pesticides or an unknown disease are the most likely causes. But he has reservations. He says that pesticides do not usually accumulate enough in mammals (which vultures eat) to do the damage – unless the pesticide dose is extremely heavy. On the other hand, vultures have not been so hard hit elsewhere in the world. He is now trying to catch vultures at Bharatpur so that he can examine them and test the theories. Meanwhile, he says: “We are just speculating. I am still not sure what is happening.”
The case of the disappearing vultures is therefore far from being solved. It looks like a worldwide problem; but it is especially serious in India because sacred cows cannot be used for human food when they die. Other scavengers such as dogs, crows and kites do not do such a thorough cleaning job on carcasses – and populations of street dogs will mushroom if their food supplies increase significantly, further exacerbating public health problems.
Vultures are not usually thought of as desirable birds worth protecting, and it may seem strange to think of them as endangered. But it must be better to have them standing menacingly on top of Delhi’s Moghul tombs, waiting patiently for their next meal, than to have dead cows and buffalos rotting by the roadside.