Fall of the House of Vultures (And How We Can Stop It)

On a crisp winter afternoon, the ravines along the Chambal River, marking the border between Rajasthan and Madhya Pradesh, were ablaze with the golden rays of the sun. Basking on sandbanks and exposed rocks were muggers, gharials, and river turtles. Perched high on the canopy of a tall leafless silk cotton tree on the ravines’ edge was a flock of Egyptian vultures. Two took off and soared over the Chambal and ravines in increasingly larger concentric circles. Perhaps they were looking for food. Vultures being obligate scavengers, we can assume that the leftovers of dead cattle would serve them well as dinner. But since the 1990s, for many unsuspecting vultures, that cattle carcass meal would turn out to be their last supper, laced as it was with a veterinary drug toxic to them.

Why we need vultures

India is home to the largest livestock population in the world. A major proportion of India’s livestock is cattle — cows, buffaloes, and hybrids. Cattle form a vital part of the daily life and livelihood of the population, as they serve as draught animals, sources of milk, meat, and leather.

As much as we need healthy cattle, we also need healthy vulture populations to clear carrion from our environment. Until the early 1990s, India had tens of millions of vultures belonging to nine species. Of these, the white-rumped vulture was the most common large raptor globally.

By feeding on carcasses, vultures provide the invaluable ecosystem service of cleaning the environment; they provide health benefits to human populations by regulating diseases and pests. In Europe, for instance, vultures provide services worth about 1,600,000 euros (about INR 13.40 crores) annually just by removing natural carrion.

The rise of diclofenac

In the mid-1990s, diclofenac, a non-steroidal anti-inflammatory drug (NSAID), was introduced to treat cattle. Diclofenac remains in the tissues of cattle for a few days after treatment. If cattle undergoing treatment die, the diclofenac left in their tissues acts as a poison for vultures that eat their carcasses. The drug causes necrosis of the kidneys and visceral gout (uric acid accumulation in tissues) in vultures. By 2004, several scientific publications proved that veterinary use of diclofenac was the leading cause of that decade-long population crash that wiped out up to 99.9% of the vulture population of India. Millions of vultures had dropped dead, albeit unintentionally or accidentally.

In 2006, the Government of India banned diclofenac, one of the first identified vulture-toxic drugs. Parallelly, through the Action Plan for Vulture Conservation (APVC), vulture conservation breeding programmes were initiated as insurance against the imminent extinction of select Gyps vultures.

However, diclofenac still found its way into cattle as veterinary treatments in India continued to include the hidden use of it and other vulture-toxic drugs. Added to this, the tendency to overdose ailing cattle with vulture-toxic drugs further compounded the issue.

Wild vulture populations in India have struggled to survive and recover from the population crash. Despite the ban on diclofenac, the environment was not free from contaminated carcasses. After nine years, in 2015, the multi-dose human-use form of diclofenac was restricted to vials of no more than 3 ml to discourage the misuse of human formulations for veterinary purposes. Since that ban, surveys are finally showing a gradual decline in the prevalence of diclofenac in the environment and a reduced rate of vulture population decline. Finally, a ray of hope!

The dangers that lurk

There are at least 14 other NSAIDs in veterinary use across South Asia. Of them, aceclofenac is of particular concern. When cattle are treated with aceclofenac, it converts almost totally into diclofenac within a few hours. Other NSAIDs, such as nimesulide and ketoprofen, have also been proven to cause kidney failure and visceral gout, leading to the death of vultures. So far, two drugs, meloxicam and tolfenamic acid have been assessed as vulture-safe. It is important to acknowledge that certain drugs, be they for human or veterinary use, might have some side effects with medically acceptable implications on the primary subject. The fact that the same drugs, especially when widely administered beyond recommended dosages, might have serious health implications (or worse, be fatal) at secondary levels is often ignored. Such ignorance is costing humanity the most efficient and naturally available “sanitary engineers” of our environment.

Even after the catastrophic vulture population crash caused by diclofenac, safety-testing of other similar drugs is yet to become a priority. Of the veterinary NSAIDs used freely for cattle treatment, only a few have been confirmed to be vulture-toxic (e.g., aceclofenac, ketoprofen, and nimesulide). Even if these drugs are banned altogether, the other drugs, some of which are likely to be vulture-toxic, such as flunixin, carprofen, ibuprofen, phenylbutazone, etc., might continue to impede the path of vulture population stability and recovery. This will continue to cost the public and the government heavily in terms of increased expenditure for clearing carrion, managing free-ranging stray dog populations, and in turn, increasing incidences of dog bites and the spread of diseases like rabies.

Breeding programmes

Conservation breeding programmes of threatened vultures were initiated by the MoEF&CC and Bombay Natural History Society (BNHS) with support from relevant state governments and facilitated by the Central Zoo Authority (CZA). The Jatayu Vulture Conservation Breeding Centre was started in Pinjore, Haryana. Other Vulture Conservation Breeding Centres were created in Rajabhatkhawa in West Bengal, Rani in Assam (with additional support from RSPB), and Bhopal, Madhya Pradesh. The successful breeding of three “Critically Endangered” vulture species has been achieved over the past 15 years, with the breeding centres holding nearly 700 captive-bred vultures. Provisional Vulture Safe Zones (VSZs) and release zones have been identified around the breeding centres. These are areas where wild vultures exist, and their population is stable. Regular monitoring of vulture populations, nests, nesting colonies, and the carcasses of domestic cattle is undertaken in the VSZs. Also, education and awareness events are held with local communities, veterinary staff, students, and forest departments, to encourage vulture-safe practices in the VSZs.

Solutions at hand

Despite successful conservation breeding, these vultures cannot be released back into the wilderness right away due to the prevalence of vulture-toxic NSAIDs. Until the food sources of vultures are free from poisonous drugs, releasing captive-bred vultures into the wild has a high risk of mortality. The cost of feeding and maintaining infrastructure for about 700 vultures isn’t nominal. Government authorities and veterinary pharmaceutical manufacturers must reconsider and adopt a more socio-ecologically responsible, sensitive, and nuanced approach to vulture-toxic NSAIDs. Like diclofenac, perhaps a ban on the rest of the proven vulture-toxic NSAIDs is the next logical step. The Government of Bangladesh, for example, has already banned ketoprofen in 2021 due to vulture toxicity. In 2015, the Directorate of Animal Husbandry & Veterinary Services, Government of Tamil Nadu, prohibited the use of ketoprofen in the Nilgiris, Erode, and Coimbatore districts, which are vulture strongholds. Shifting to vulture-safe meloxicam and tolfenamic acid for veterinary purposes and gearing up safety-testing of other drugs that are vulture-safe options seem to be the sensible ways forward.

With inputs from Vibhu Prakash (Head of Vulture Programme, BNHS), Christopher Bowden (Globally Threatened Species Officer, RSPB) and Bivash Pandav (Director, BNHS).