Guwahati, Aug. 27: A chemical called diclofenac sodium used in the preparation of pharmaceutical drugs is said to be the probable cause of the mortality of vultures.

This was announced at the sixth World Bird Conference in May, according to Nasser Ahmed, wildlife co-ordinator, College of Veterinary science, Assam. “Vultures are very sensitive to this chemical which is used in human and veterinary medicines. Traces of this chemical might be present in the carcass which the vulture picks on,” he said.

There are nine species of vultures in Assam and all of them, especially the white-backed and long-billed vulture, have disappeared in recent years. In 1995, the forest department recorded 86 vultures in the Assam state zoo, but these are not to be seen anymore.

Robert Risebrough of the University of California, who visited Boko, said, “There is an immediate need to see that vultures survive, maybe through captive breeding. A combination of pesticides is surely responsible for this decline.”