January 24, 2007
vanishing vultures
As my previous post was about the unintended consequences of biochemicals in the environment (specifically, in the rivers), this entry is also along those lines...
Yesterday, I received the latest ish of Smithsonian magazine (Feb 07). One of the articles (by Susan McGrath) is about vultures in India and Pakistan that have been disappearing at dramatic rates. 15 years ago, there were tens of millions. Today, there may be only less than half a million.
[picture of slender-billed vulture by Asad Rahmani / BNHS]
"...three vulture species...serve as sanitation engineers in India, Nepal and Pakistan. For thousands of Years, they have fed on livestock carcases. As many as 40 million of the birds once inhabited the region. Obstreperous flocks of vultures thronged caracass dumps, nested on every tall tree and cliff ledge, and circled high overhead, seemingly omnipresent. In Delhi, perching vultures ornamented the tops of every ancient ruin. In Mumbai, vultures circled the Parsi community's hilltop sanctuary. Parsis, who are members of the Zoroastrian religion, lay their dead atop stone Towers of Silence so that vultures can devour the flesh. This practice, according to Parsi tradition, protects dead bodies from the defiling touch of earth, water or fire."
So what happened?
After painstaking investigation, biologists and zoologists from India, UK, and US discovered that a recently-licensed painkiller (nonsteroidal anti-inflammatory drug), diclofenac, was being used by herders to treat their livestock. This drug turned out to be deadly for vultures.
Those livestock who soon died despite treatment were skinned and left for the vultures, as was customary. Investigators found that more than enough drugged carcasses existed to kill vultures at the rate observed.
The result is that:
"...across the subcontinent...vultures are disappearing. Dead livestock lie uneaten and rotting. These carcasses are fueling a population boom in feral dogs and defeating the government's efforts to combat rabies. Vultures have become so rare that the Parsi in Mumbai have resorted to placing solar reflectors atop the Towers of Silence to hasten the decomposition of bodies. International conservation groups now advocate the capture of long-billed, white-backed and slender-billed vultures for conservation breeding."
(It just so happens that for the past month or so, I've been corresponding with a retired Parsi from Mumbai. I'll have to ask him about this vulture problem.)
Posted by raacluse at January 24, 2007 09:46 PM