Nepal is home to around 15,000 to 20,000 vultures.

The white-rumped and slender-billed vultures are among them. Vultures are scavengers, which feed on the carcasses of large animals, thus playing an important role in cleaning the environment. Studies have found that around 90 per cent of the white-rumped and slender-billed vulture population has declined from 1995 to 2009. In recent years, the government and the private sector have made efforts towards vulture conservation. Vulture breeding centres have been established, so have vulture restaurants and vulture conservation foundations.

The main threats to the survival of vultures in Nepal include the veterinary use of the analgesic diclofenac, habitat destruction, pesticide pollution, slow breeding rate, paucity of carcasses, feeding on poisoned carcasses and lack of legal protection.

Studies suggest that diclofenac, an anti-inflammatory drug widely used to treat pain in livestock, is the prime cause of the vulture's decline. Vultures are exposed to diclofenac when they feed on carcasses of livestock containing toxic residues of the drug. When vultures consume diclofenac-contaminated flesh, their kidneys stop functioning, leading to their death.

Pesticide pollution is also a threat to Nepal's vultures. DDT (dichloro-diphenyl-trichloroethane), which is used as a pesticide, enters the body of vultures through the food chain, where it affects the activity of the estrogen hormone. As a result, premature hatching of eggs takes place, causing the death of the embryo. As a vulture generally lays a single egg in a breeding season, their breeding rate is naturally slow.

Use of poisoned carcasses as bait to kill cattle-marauding carnivores is also a threat to the vultures. Feeding on the carcasses of these poisoned animals can be fatal.

The disappearance of the ecologically-important vultures is a matter of concern. The increase in the number of feral dogs has shown to be proportional to the decline in the number of vultures. And with this, there is an increase in the incidence of rabies-related deaths.

Also, the multiplication of feral dogs has led to an increase in leopard assaults on them, leading to human-wildlife conflict.

Though the government has banned the use of the culprit drug diclofenac by recommending meloxicam as its substitute, the former is still sold illegally and is frequently being used by the cattle farmers in Nepal.

There is, thus, a need to develop an effective substitute for diclofenac, and the present available substitute, meloxicam, needs to be subsidised.

A version of this article appears in the print on April 29, 2021, of The Himalayan Times.