Andrew Routh, Thursday 9th August

The decline of vulture populations in India

When was it first noticed that there was a decline in vulture populations?

Years ago vultures would be a regular sight flying over head however it was only in 1999 that it was noted that there had been a significant decline in numbers, in fact for one species it was thought that there was only 0.03% of the original population left.

What species of vultures were you looking at?

Oriental white backed, slender billed and the long billed vultures.

What investigations were done to try and find the cause of the decline?

ZSL helped with investigating the cause of the decline and there were two reasons discovered; pathology reports showed birds had died from kidney failure or had died from flying into power cables. The birds that had died from kidney failure were also found to have a drug called diclofenac in their bodies; however the ones that had died from flying into power cables did not. So it was thought that the drug was the cause of the kidney failure.

What is the drug used for?

Diclofenac was originally used as an anti-inflammatory drug for humans and then had started to be used for veterinary treatment more recently. As cows aren’t eaten in India and only farmed for their milk, when they die they are often just left in the fields or put in cattle dumps as the vultures would then come and clean everything up. Although this drug is perfectly safe to use for cattle it was not safe for the vultures and therefore once the vultures consumed a cow that had taken the drug it would cause kidney failure in the vulture.

What was done then to try and change the situation?

Once the cause of the problem was sourced research could then be done to find an alternative to using diclofenac in agriculture. These alternative drugs are being offered to farmers and distributors in exchange for their stores of diclofenac to stop it being used.

Has the situation changed and are the vulture numbers increasing again?

There is some evidence of vultures still being poisoned by diclofenac and the population numbers still have not risen. There are also other factors that are causing vultures to be injured or killed such as flying into power cables, being shot around army bases as they damage planes if they have collisions with them and also from the Indian kite festival.

What is the Indian kite festival?

The festival happens all over India and involves a huge number of people flying kites up to 50-100 meters in the air. The vultures can fly into the kite strings, which can cut through soft tissue, and hundreds of birds get injured in this way. 10-15 years ago this would have been a welfare problem but now it is also a conservation problem. However the injured vultures are taken to breeding centres across India and treated. These injured birds cannot be released back into the wild but can then be part of a breeding program for the vultures. ZSL aims to breed 200-300 birds of each of the three species of vulture that were affected. They can then look into reintroducing the vultures once the drug problem has been resolved.