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ENVIRONMENT:
VULTURES
Fatal
Affliction
A dramatic
population crash leads scientists to believe that the cause may be a deadly
virus. But doubts remain.
By Vijay
Jung Thapa
Call
it Operation Sick Scavenger. Over the next few months, forest officials,
wildlife activists and volunteers will scour the Indian countryside looking
for dying or dead vultures. They will comb the dense bushes, climb up
scraggy trees and camp around smelly carrion looking for these unhealthy
creatures of feather. Once these birds are trapped, they will be transported
to the Poultry Diagnostic and Research Centre in Pune where scientists
will carry out a variety of tests to try and confirm the presence of an
infectious disease or virus that's affecting vultures en masse.
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| THREATENED
SPECIES: Pesticides or a virus are to blame |
If the investigators find conclusive evidence to show that all these sickly
or dead vultures were afflicted with the same disease, it will do two
things. It will unilaterally confirm that the huge decline in the Indian
vulture population is due to an infectious disease. And it will caution
that this disease or virus could well be passed on to other species like
poultry or humans.
Vultures rarely figure in anybody's list of the most popular birds but
over the past few years ornithologists have been concerned about their
dramatically dwindling numbers. No one was sure about the extent of the
decline until recent surveys done by researchers attached with the Bombay
Natural History Society (BNHS) showed vulture populations in some areas
had fallen by more than 95 per cent. The Indian subcontinent is known
to have eight vulture species, out of which two are on the fast track
to extinction. They are the white-backed vulture and the long-billed vulture.
Says ornithologist Vibhu Prakash of BNHS, author of one such study conducted
in the Keoladeo National Park in Bharatpur: "In specific places,
where earlier I could see thousands of vultures feeding on carrion, today
there are less than 50."
Initial investigations of this population crash seemed to point towards
the large-scale use of pesticides. Toxicology studies suggest it may be
true-tests show that cattle ingest DDT after which the pesticide moves
into the vulture's system. Besides, vulture tissue samples show four times
more pesticides than, say, pigeons. Reports also indicate vultures aren't
an exception and the same affliction is bothering sarus cranes, ring doves
and eagles. But all experts aren't buying this theory. Vultures are nature's
incinerators and for this they possess an extraordinarily strong digestive
system that can absorb the strongest pesticides. In fact, this is what
makes them so important in a country like India. They dispose of a potential
source of disease-the carrion-and recycle the nutrients contained in the
carcasses. Experts suspect a viral epidemic because only an infectious
disease could, they feel, cause such a sudden decline in numbers.
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