When Vultures Die, We Die

To put this in perspective, the atomic bombs dropped on Hiroshima and Nagasaki killed about 214,000 people. In 20 years since the Iraq invasion, between 280,000 and 315,000 people are estimated to have died from war-related violence.

Titled The Social Costs of Keystone Species Collapse: Evidence From The Decline of Vultures in India, the study is due to be published in the forthcoming issue of American Economic Review. It details what happened when India faced the functional extinction of vultures.

Ecologists call the disappearance of large populations of a species ‘functional extinction’. It is a condition when only so few are left that they can no longer serve their ecological function.

“The study shows us how damaging it can be when non-human species disappear. We need to realise this in the future,” Anant Sudarshan, associate professor of economics at the University of Warwick in England and co-author of the study, tells IndiaSpend.

The backstory

Vultures are a keystone species in India--that is, they define an entire ecosystem, making the survival of other species possible. Conversely, their absence completely disrupts an ecosystem. A keystone species could be a plant, or a predator. In India’s case, it is the vulture.

India was home to an estimated 40 million vultures in the 1980s, according to this document from the Ministry of Environment, Forest and Climate Change. Nine of the world’s 23 species of vultures exist in India; five of them belong to the genus Gyps and the rest are monotypic (that is, a genus that contains only one species).

Vultures play a critical ecological role as scavengers, and are cultural totems. Hindus revere Jatayu; Zoroastrians, who believe the earth and water are sacred, don’t defile them with their dead; instead, they place their dead on the Tower of Silence in Mumbai, to be eaten by vultures. By feeding on the carcasses of cattle, dogs and other animals, vultures clean up the environment, effectively getting rid of carcasses that are breeding grounds of pathogens. Their presence makes human habitats livable.

All of this began to change in the early 1990s, when the non-steroidal anti-inflammatory drug (NSAID) diclofenac was permitted for veterinary use as a painkiller. Farmers and vets started using it widely on livestock to treat fever and inflammation. Within 15 years of diclofenac entering the bloodstream of animals and, through their carcasses, into vultures, the vulture population collapsed. Catastrophic losses mounted for four of India’s nine species of vultures: three Gyps vulture species and the red-headed vulture.

“By the beginning of 2004, it was clear that diclofenac was the main cause of the catastrophic decline of vultures,” Chris Bowden tells IndiaSpend. Bowden is coordinator for the Asian Vulture Programme in South Asia, and programme manager for SAVE (Saving Asia’s Vultures from Extinction). He is the Globally Threatened Species Officer for the Royal Society of Protection of Birds (RSPB).

The catastrophe was so marked that a population numbering in the tens of millions was reduced to a few thousand in the span of just five years. “The populations of four vulture species found in India and endemic to Asia have undergone such dramatic declines since the 1990s that they are now at the most severe risk of global extinction – ‘Critically Endangered’,” according to a SAVE policy brief.

Diclofenac is a death pill for vultures. When a vulture eats a diclofenac-laden carcass, Bowden says, the drug causes kidney failure in a day or two and the bird dies.

Although veterinary use of diclofenac was banned in India in 2006, lack of enforcement means the drug is still prevalent, and continues to exact a heavy toll. Bowden points out that despite the ban, there is no quantifiable recovery of the birds in India whereas Nepal, which has effectively enforced the ban on diclofenac and other toxic alternative drugs, has seen a strong recovery of the vulture population.

Vulture species

Source: Save-vultures.org

The dominoes fall

As vultures vanished from the Indian landscapes, the carcasses piled up on land, and floated, bloated, in the waters. By the side of water bodies, rotting meat stacked up and filled the air with a nauseating odour.

The paper cites a report which says, “Huge dumps have sprouted near urban centers where thousands of dead cows, along with the occasional horse or camel, are brought to rot.”

Pathogens flourished; dogs fed on the carrion and their numbers increased; more dogs meant more dog bites, which meant more rabies and more deaths of people. As per the paper, 36% of global deaths from rabies still occur in India. Simultaneously the rat population increased, becoming another carrier of disease and death.

“There has been a fair amount of discussion in the ecology literature for several years on why the disappearance of vultures is causing more rabies, more disease, and worse sanitation,” says Sudarshan. “Our study starts from these concerns and aims to quantify the effect on deaths, if any.”

India has been a diclofenac-wrought natural experiment.

Sudarshan explains that they looked at districts whose habitats were suitable to support vultures and compared them to those that were not. In the latter case, the extinction of vultures would have little effect, since the birds were not present before. In the former case, though, there would be a change in death rates once the services of vultures were removed.

The authors compared the two groups before and after the entry of diclofenac into the veterinary market, and found that while death rates were similar in both areas before, they began to diverge after the extinction of the birds. Mortality rates grew higher in vulture habitats where the bird population was shrinking.

In their estimates, they say, they find “an implied average annual increase of 104,386 deaths due to the decline in vultures in the high-vulture suitability districts”. Additionally, they find the mortality damages to be $69.4 billion a year.

Sudarshan says collecting the required data was difficult because India does not have good quality and easily accessible information on district-level death rates going as far back as the 1980s and 1990s.

Toxic landscapes, dead vultures and people

Although vultures face threats such as accidental killing by poison baits and collisions and electrocution due to power infrastructure, the main issue according to SAVE and Chris Bowden remains the veterinary use of vulture-toxic NSAIDs including nimesulide and aceclofenac, and also diclofenac, which was still being used even in 2017, despite its ban in 2006.

At least two similar and equally affordable veterinary drugs (meloxicam and tolfenamic acid) have been found to be safe for vultures. Despite this availability of viable alternatives, NSAIDs like aceclofenac, nimesulide, ketoprofen, and flunixin that have been proven to be toxic to vultures continue to be used.

In 2023, veterinary use of aceclofenac and ketoprofen was banned in India, but the lethal nimesulide and flunixin are still legally in use, as are other drugs of unknown toxicity.

In an order dated September 1, 2023, the Delhi High Court directed the Union government to furnish reasons for why nimesulide had not been banned. In its order in December 2023, the Court said the petition stood satisfied as the Union government “prohibited the manufacture, sale and distribution of ‘Nimesulide’ in nearly all its combinations and usage for human use”.

The Drugs Technical Advisory Board (DTAB), the expert body that advises the drug regulator on technical matters, in its January meeting this year, recommended a ban on the use of all formulations of nimesulide for veterinary use. The DTAB also called for research into the effect of nimesulide on people. However, nimesulide remains in circulation as does flunixin, which is toxic to Gyps vultures, according to the toxicity report from SAVE.

IndiaSpend wrote to the Drugs Controller General of India about the DTAB’s recommendation to ban nimesulide, asking if any action is proposed to be taken, and if so when. We will update this story when we receive a response.

Commonly used NSAIDs in veterinary practice in India

Source: Save-vultures.org

Steps to vulture conservation

India has a vulture breeding programme jointly run by government agencies and the Bombay Natural History Society (BNHS).

“The breeding programme is an important safety net for these threatened vulture species, and it needs careful ongoing management,” says Bowden.

However, the situation remains precarious for vultures. Evidence shows that the use of toxic NSAIDs continues illegally. Because vultures travel great distances, it isn’t safe to assume that anywhere is safe for them. Thus, we are not at a stage where vultures bred in captivity can be safely released.

What’s more, Bowden says, it is quite possible that other toxic drugs will be introduced to veterinary use, and because it takes so long to test and ban drugs, any such remedial action could be too late. Thus, there is the need for drug testing and regulation before licensing, not after.

“Despite coordinated regulatory action by governments to ban veterinary diclofenac in South Asia, enforcement has been incomplete in many areas,” according to the paper published in the journal Ecological Solutions and Evidence. “Progress in preventing the veterinary use of other NSAIDs now also known to be vulture toxic has been slow. A mosaic of inconsistent licensing processes currently exists across South Asian vulture range states, leading to issues with successful policy implementation, legitimacy and effectiveness.”

The Action Plan for Vulture Conservation in India 2020-2025 is comprehensive. Its objectives include “removing the main causative agent for vulture mortality – diclofenac; curbing leakage of human formulation of diclofenac into the veterinary sector; monitoring conservation and recovery of vulture sites; setting up and expanding vulture care and breeding centre,” among others.

What next for vultures and people?

“Vultures are not safe, but they will not go extinct,” says Vibhu Prakash, the scientist who first noticed vulture deaths in his field work. He was with BNHS for over four decades and headed the Vulture Conservation Programme till his retirement in 2020.

Prakash says if the Action Plan is implemented, then vultures can have strong chances of recovery. He says nimesulide should immediately be banned, and every drug should be tested to see if it is safe for vultures before being introduced.

Bowden emphasises that there are effective, out-of-patent alternative drugs that are not toxic to vultures. Meloxicam and tolfenamic acid are examples of such drugs that have already been tested, and such testing should be done before and not after these drugs have been licensed for veterinary use, as recommended by the Convention of Migratory Species in 2020.

Banning veterinary drugs is a cumbersome process. As things stand today, diclofenac was banned in 2006 and was gazetted in 2008. The restriction of vial size of human formulations was passed in 2015. All of that didn’t come easy. The BNHS filed the original case with help and support from numerous parties at various stages, according to the report from SAVE. After years of submitting evidence and repeated requests from many organisations, bans on veterinary use of ketoprofen and aceclofenac came through in 2023.

The authors of the paper emphasise testing before putting out chemicals into the environment. They say that in retrospect, “it is plausible that a counterfactual policy regime in India that tested chemicals for their toxicity to at least keystone species might have avoided the collapse of vultures.”

The most immediate steps, Bowden says, are removing diclofenac completely and totally from the food chain of vultures through strict enforcement and making sure that that the unsafe drugs--aceclofenac, nimesulide, ketoprofen, flunixin and carprofen--are not supplied to government veterinary hospitals.

If the vultures are fine, we humans are safe.

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