One of the most dramatic examples of species collapse in recent history is the decimation of vulture populations in India. Over less than a decade starting from the mid-1980s, a population of over thirty million white-backed vultures fell to several thousands, and 11 out of 16 vulture species across the world are now at risk of extinction.
The near total disappearance of vultures has significant and insufficiently understood costs. Vultures feed on animal carcasses. In the absence of this scavenging service, carcasses frequently rot in the open, leading to an increased disease burden and associated mortality. Without vultures, carcasses remain available as a food source to animals, namely feral dogs that transmit rabies. Over 36 per cent of global rabies deaths occur in India and the country has set up a dedicated rabies mission to tackle the problem.
High level of acidity in the stomach of vultures acts as a disinfectant, which kills harmful bacteria. With the decline in vulture population, humans are more at risk of getting exposed to such pathogens. Any water source that is dependent on surface runoff is at risk of contamination from carcasses that are not quickly disposed of by vultures.
The loss of vultures may also impose costs on India’s leather industry, with small manufacturers, used to rely on vultures to dispose of animal carcasses, but is now forced to find alternative and more expensive solutions. Moreover, the disappearance of vultures has caused a direct impact on one of India’s most important cultural minorities, the Parsi population, who have used vultures to dispose of their dead for thousands of years. Without a flourishing vulture population, a fundamental religious practice for this community has all but ended.
Why this study
Saving vultures has become a growing policy priority in India. In 2006, the Indian government banned dicoflenac for veterinary use, a highly consequential decision given the popularity of the drug in treating India’s vast rural cattle population, about 300 million. In 2018, the government went a step further and placed a ban on all uses and manufacturing of the drug. In both cases, government action attracted widespread litigation.
The evidence produced by this project will be crucial in providing a scientific basis to these policy measures, while also providing guidance on the value of allocating scarce resources towards growing the vulture population in the country.
This project will identify the causal link between vultures and the health and productivity costs. To do so, the researchers will combine ecological models of species distribution combined with vulture observations in the wild, with rich data on all-form mortality, causes of death, small-scale leather enterprise, and population counts of cattle and rabid dogs.
After constructing vulture distribution maps and mortality data, they will develop district-level data on water quality, rabies infections, and livestock as well as dog population counts (recorded in the livestock census).