No more vultures circle the Towers of Silence in Delhi

The Parsi community of northern India have a unique burial tradition. They put their dead out at the sacred Towers of Silence and the vultures that constantly circle, sometimes turning the sky dark by their numbers, devour the flesh on the bodies until the bones are picked clean and white. This tradition dates back centuries but is shortly to end if we're not careful.

Since the 1990s the vulture population all over South Asia has rapidly depleted to the point where 99.9 per cent of them have died. For several years no one understood the phenomenon, but in 2003 a scientific study of the post mortems conducted on vulture corpses in Pakistan made a breakthrough. The anti-inflammatory antibiotic drug widely used on cattle diclofenac, produced by the Swiss company Pfizer and sold at a discount in South Asia, had produced a toxic reaction in the vultures that fed on the cattle carcases. The drug is highly beneficial to cattle and, for that matter, to humans. It has a short half-life, produces no toxic waste and has few side effects. No wonder it rapidly grew popular amongst Indian and Pakistani farmers. But when red meat containing the drug, and some others like it, are eaten by vultures, despite their notoriously resilient digestive systems which can processes all manners of other substances in meat that would be toxic to humans, it causes uric acid to form and that quickly leads to renal failure and the vulture dies. Hence the collapse in vulture numbers. Vultures breed only once a year and produce only one egg. To restore their numbers, even if the causes of their decline were eradicated, would take a hundred years according to environmental filmamker, Mike Pandey, who drew this sad story to my attention. The benefits to humans once more in conflict with the welfare of the natural world and the natural order.

But the story gets more complicated on closer scrutiny. Vulture numbers are also depleting in countries such as South Africa where diclofenac is not in common use. Here this has been attributed to power lines, climate change and, controversially, to the harvesting of vulture body parts for medicinal purposes by Sangoma, traditional Southern African healers. Nor would simply banning the drug necessarily solve the problem according to scientists. No one knows whether the substitutes may have the same, different or worse effects.

So the large, dark vultures, with their priestly white collars, once so common circling hopefully and watchfully in the shimmering, hot, white-grey Northern Indian sky have gone and a deeper silence has fallen on the Towers of Silence.