Vultures are scavenging birds, feeding mostly on the
carcasses of dead animals. Vultures are found in every continent except
Antarctica and Oceania.
A particular characteristic of many vultures is a bald head, devoid of feathers. This is likely because a feathered head would become spattered with blood and other fluids, and thus be difficult to keep clean.
A group of vultures is occasionally called a venue in literature. When circling in the air, a group of vultures is
called a kettle. The German word Geier does
not have a precise meaning in ornithology, and is sometimes used to refer to a vulture in
English, as in some poetry.
Classification
Vultures are classified into two groups: Old World vultures and New World vultures. The similarities between the two different
groups are due to convergent evolution.
Old World vultures
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The Old World vultures found in Africa,
Asia and Europe belong to the family Accipitridae, which also includes eagles, kites, buzzards and hawks. Old World vultures
find carcasses exclusively by sight.
New World vultures
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The New World vultures and condors found in warm
and temperate areas of the Americas are not closely related to the superficially similar
Accipitridae, but belong in the family Cathartidae, which is quite close to the
storks. Several species have a good sense of smell, unusual for raptors.
Feeding
Vultures seldom attack healthy animals, but may kill the wounded or sick. Vast numbers have been seen upon battlefields. They
gorge themselves when prey is abundant, till their crop bulges, and sit, sleepy or half
torpid, to digest their food. They do not carry food to their young in their claws, but disgorge it from the crop. These birds
are of great value as scavengers, especially in hot regions. They can eat rotten flesh containing anthrax, botulism, and cholera bacteria,
which are destroyed in the stomach [1].
Threat due to diclofenac poisoning
Some members of both the old and new world vultures have an unfeathered neck and head, shown as radiating heat in this
thermographic image.
The vulture population in India and Pakistan has declined
by up to 95% recently in the past decade, and two or three of the species of vulture in South Asia are nearing extinction. This
has been caused by the practice of giving working farm animals diclofenac, which is a
non-steroidal anti-inflammatory drug (NSAID) with anti-inflammatory
and pain killing actions. Diclofenac administration keeps animals that are ill or in pain working on the land for longer, but, if
the ill animals die, their carcasses contain diclofenac. Farmers leave the dead animals out in the open, relying on vultures to
tidy up. Diclofenac present in carcass flesh is eaten by the vultures, which are sensitive to diclofenac, suffering kidney
failure, visceral gout, and death as a result of diclofenac poisoning.
The decline in vultures has led to hygiene problems in India as carcasses of dead animals now tend to rot, or be eaten by rats
or wild dogs, rather than be tidied up by vultures. Rabies among these scavengers is a major
health threat. India has the world's highest rate of rabies.
The decline in vultures causes particular problems for certain communities, such as the Parsi,
who practice sky burials, where the human dead are put on the top of Towers of Silence and are eaten by vultures, leaving only dry bones.
Meloxicam (another NSAID) has been found to be harmless to vultures and should prove an
acceptable alternative to diclofenac. The Government of India banned diclofenac, but it continues to be sold over a year later
and is still a problem in other parts of the world.[2]
Vultures in culture
Ancient Egypt
In Southern Africa, the name for a Nubian vulture is synonymous with the term
applied to lovers, because these vultures are always seen in pairs, mother and child remaining
closely bonded together. Pairing, bonding, protecting, and loving are essential attributes associated with the vulture's size and
its ability to soar high up in the sky. The Egyptians considered the vulture an excellent mother,
and its wide wingspan was seen as all-encompassing and providing a protective cover to its infants. The vulture hieroglyph
was the uniliteral sign used for the glottal sound (3) including
words such as mother, prosperous, grandmother, and ruler
In the Western world, the image of the vulture is far more negative, with 'vulture' used as a metaphor for those who prey on
the weak or dying, with associated negative connotations of cowardice and selfishness (although the vulture plays an important
natural role).
References
- Ferguson-Lees, Christie, Franklin, Mead and Burton Raptors of the World ISBN 0713680261
- Grimmett, Inskipp and Inskipp, Birds of India ISBN 0-691-04910-6
- Hilty, Birds of Venezuela, ISBN 0-7136-6418-5
- Ian Sinclair, Phil Hockey and Warwick Tarboton, SASOL Birds of Southern Africa (Struik 2002) ISBN 1-86872-721-1
- NSAID effects on
vultures (BBC website)
- "India's Vultures Fall Prey to a Drug in the Cattle They Feed On", New York Times, Amelia Gentleman, March 28, 2006.
External links
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