Veterinary non-steroidal anti-inflammatory drugs (NSAIDs), particularly diclofenac which is used to treat cattle in some countries, are largely responsible for the extreme decline in vulture populations in South Asia in recent decades. In India and Nepal, cows are not eaten by humans due to their status as sacred animals but for vultures, they are a main food source. Vultures who consume the carcasses of cattle treated with diclofenac suffer kidney failure. When researchers began noting the link and calling for a ban on the drug, proponents of its use proposed alternate theories for the vultures’ near extinction numbers including feral dogs (feral cats apparently unavailable in this rare instance, presumably due to the laughability factor):
A common finding at carcass dumps is the presence of other scavengers, particularly feral dogs, and it has been proposed that the decline in vultures is due to the increase in feral dogs (Chhangani and Mohnot, 2004). However, vultures and dogs have always coexisted at carcass dumps in India, and in over eight years of observations no instances of predation by dogs on vultures has been recorded. Most importantly, the increase in dog numbers only occurred after the collapse in vulture numbers.https://save-vultures.org/other-hypotheses-for-vulture-declines/
European countries follow their own discretion regarding the use of diclofenac and Spain, home to 90% of Europe’s vulture populations, approved its use in 2013. Last month, a new study confirmed the first death of a vulture in Spain due to diclofenac poisoning. Conservationists continue to call for a ban on the drug.
US readers may be familiar with diclofenac in the over the counter arthritis medicine called Voltaren. Pet owners might recognize some of the other NSAIDs, also known to be toxic to vultures:
We have evidence for the toxicity to vultures of six NSAIDs other than diclofenac, namely: aceclofenac, carprofen, flunixin, ketoprofen, nimesulide and phenylbutazone.
Meloxicam remains the only known vulture-safe NSAID.https://save-vultures.org/alerts/
Vultures play an important role in the ecosystem by clearing away dead animals, including those infected with diseases such as anthrax and rabies. When vulture populations dwindle, an imbalance occurs:
The scavengers that tend to move in where vulture populations are low include: feral dogs, rats, and blowfly larvae. While these animals do help to remove carcasses from the landscape, they are also more likely to spread disease to human populations and other animals as well. In India, for example, the feral dog population increased significantly after vultures consumed cow carcasses poisoned with diclofenac, a painkiller. These feral dogs carried rabies and went on to infect other dogs and local people. Between 1993 and 2006, the government of India spent an additional $34 billion to fight the spread of rabies. India continues to have the highest rate of rabies in the world.https://www.worldatlas.com/articles/what-is-the-role-of-vultures-in-the-ecosystem-and-wildlife-conservation.html
Support your local vultures. They support you!