Human formulations of the drug Diclofenac banned for veterinary use are still being illegally used to treat cattle, posing a grave danger to the already critically-endangered vulture population, say experts.
"Till the late 80s vultures could be seen breeding in Talkatora gardens as well in large hoards in various parts of the city. Once they were very common and we were worried about their excessive numbers. But that has changed. The population has witnessed an alarming crash over the past few decades," says environmentalist Ravi Aggarwal.
Almost 99 per cent of the scavenger birds are today on the verge of extinction, he points out.
"The annual mortality of the long living and slow breeding birds is not more than 5 per cent. However by mid 1990s and 2000, the species mortality rate ratcheted up to a high and 90 per cent of the vulture population had already disappeared," says Vibhu Prakash, who heads the vulture conservation programme of the Bombay Natural History Society.
The culprit was found to be use of Diclofenac, a drug which gets ingested into the birds body when they feed on the cattle treated with the drug forming white crystals of uric acid deposits on the vital organs.
Unable to excrete uric acid, the kidneys of the birds fail and eventually the vultures die of dehydration.
"In India, 76 per cent of the dead vultures when examined showed symptoms of visceral gout. All of them had residues of diclofenac in their body. The drug is 30 to 40 times as toxic to vultures as cyanide is to rats," says Prakash.
Taking into consideration the vulture ecology, Prakash points out that "even less than 1 per cent of the carcass which has the drug can cause the kind of crash in the population which we have seen in the country."
In 2006, the Centre came up with the Vulture Action Plan whose key recommendations included a ban on the use of diclofenac, use of an alternative drug to diclofenac and initiation of a conservation breeding plan.
But despite Diclofenac being banned for veterinary use the drug available in multi-dose vials for humans, is used illegally to treat cattle, point out experts.
The vulture conservation programme of BHNS, has bred some 300 birds, including 46 chicks, in three breeding centres- Pinjore in Haryana, Rani in Assam and in West Bengal. "The Society, he says, has set the 2016 as the target year to begin releasing its captive vultures," says Prakash.
