Drug threatening vultures

When I first began working on saving vultures in India, I did not know much about these fascinating birds. Over the years, I have observed them in the wild and captivity and found them to be only gentle, calm and cooperative, other than all the great things they do for us – humans. They are nature's most efficient scavengers, halting all the bacteria and fungus from spreading from dead animal carcasses in the environment. What is fascinating is their collective behaviour in their colony. Communicating with each other while soaring high up in the sky to find food, giving each other the space to feed on the carcass, mating for life and sharing the responsibility of nurturing an offspring are a few of the things that have awed me since the past eight years now.

Vultures were quite common till the 1980s and are fighting to survive currently. Currently, seven species in Africa and eight species in India are threatened with extinction. India has lost 99% population of the three species, white-backed vulture, long-billed vulture and slender-billed vulture. The red-headed and the Egyptian vulture populations have also crashed by 91% and 80% respectively. This catastrophic decline has been attributed to the use of diclofenac, a non-steroidal anti-inflammatory drug (NSAID) in veterinary practice during the 1990s. Vultures are exposed to diclofenac when they feed on the carcass of an animal that has been treated with diclofenac, 72 hours before its death. The drug is extremely toxic to vultures and impacts their kidneys and they die of visceral gout.

Despite, placing a ban on the veterinary use of the drug in 2006, human doses were misused for cattle treatments in the country. The prevalence of diclofenac and other toxic drugs have been closely monitored over the past many years. Though the usage of diclofenac in India has reduced considerably now, it is continued to be misused in some places. Vulture populations are still not safe as the populations are still small to recover quickly and will not survive another catastrophic event. This vulnerability is threatened more as vultures are slow breeding birds, laying only one egg a year and having a longer immaturity duration after fledging. The remnant population will only double after 10-15 years without the occurrence of any adverse events.

In the revised National Vulture Conservation Action Plan (2020-2025), the government plans to set up eight new captive-breeding centres but without a check on the toxicity of these non-steroidal anti-inflammatory drugs (NSAID) and their use (misuse of diclofenac), releasing the captive-bred populations in the wild will not be considered feasible. Thus, the government and other stakeholders need to ensure that the environment is free from drugs that are toxic to vultures. Misuse of diclofenac, use of aceclofenac which metabolises into diclofenac and is much more toxic to vultures, and another drug called nimesulide (found toxic to vultures) are being used for veterinary treatment. With more robust policies and enforcement of rules that are immediate, we can safeguard the remnant vulture populations in the country.

The use of diclofenac in Europe is threatening remnant vultures. South Asian governments and conservation organisations have taken the necessary steps in protecting and stabilising the critically endangered populations of vultures in the past two decades. A multi-stakeholder approach has given a lease of hope to conservationists on the survival of vultures. But, given that diclofenac is permitted to use in veterinary treatment in Europe and with the alarming new evidence of mortality in Cinereous Vulture due to diclofenac, it could jeopardise the efforts taken in South Asia to conserve these species. When there are alternative drugs available for veterinary treatment that is found safe for vulture species, the use of a killer drug is not a sustainable option.

Removal of diclofenac treatment in India has not proven to be a problem for animal husbandry. However, continued usage of diclofenac in other parts of the world pose a threat to species found there and the future conservation of vultures in the Indian subcontinent.

(The writer is a wildlife conservationist working with the World Wide Fund for Nature to conserve the remnant populations of vultures in India)