NATURE'S CLEAN-UP CREW
By Jeannie Marcure
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Observing a group of
Turkey Vultures cleaning up a deer carcass last fall
tweaked my interest in these carrion eaters. I have to
admit that before my research, I found these big black
birds to be a little repulsive. After all, they eat dead
and decaying things and I’d also heard a rumor that they
sometimes vomit on people. Not a pretty
picture—especially when you consider their diet! My
reading led me to the website maintained by The Turkey
Vulture Society of America and revealed some truly
amazing and unexpected facts.
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Although United States is
home to three kinds of vultures, the California Condor,
the Black Vulture, and the Turkey Vulture, only the
Turkey Vulture is found here in Western Montana. These
seasonal residents usually head south with the Autumnal
Equinox and return with the Vernal Equinox and like the
Capistrano Swallows, often return to their roost on that
exact day. Turkey Vultures can often be spotted on fence
posts or in trees near road-killed game. At 25-32 inches
and with a naked red head, they are easy to identify.
They can also commonly be seen soaring overhead,
scanning for another meal. In flight they can be
recognized by the dihedral (V) shape of their wings and
by the fact that they seldom flap their wings—rather
relying on thermals and updrafts to keep them aloft.
Most other large soaring birds hold their wings straight
and flap frequently. TV’s feel the air with the wing-tip
fingers allowing them a soaring skill much admired and
envied by experienced glider pilots.
The Turkey Vulture is family oriented and a group of
vultures living together and sleeping at night in a tall
tree is called a roost. Some roosts are known to be 100
years or more old. This means that the same family has
used the same tree or trees as home for many
generations. However, during nesting, a mating,
monogamous pair goes off by themselves to lay two eggs
and raise their young. They do not build nests as such
but rather lay the eggs on the bare ground. Nests are
often found on ledges on the face of a cliff, in a cave,
a hollow tree or even in an abandoned building.
According to the Turkey Vulture Society website at:
www.accutek.com/vulture/facts , Turkey Vultures seem
to live and work in cooperation and friendship and when
there is a big feast available they somehow contact
neighboring roosts to share the plenty. One observation
near three dead cows reported three roosts feasting and
living together until the carcasses were clean. They
also seem to like human contact and often choose roost
sites near humans. Turkey Vultures that have been
injured and taken to rehab often become very attached to
their handlers and follow them around much like a pet
dog would.
Although the Turkey Vulture has acquired a reputation
for vomiting, the truth is that it seldom regurgitates.
However if it is cornered and feels threatened, a TV may
roll over and play dead or it may project an offensive
smelling vomit in a defensive manner. Mostly silent
except when threatened, TV’s hiss to warn off enemies.
Despite these somewhat questionable behaviors and the
fact that they regard dead animals as fine dining, the
Turkey Vulture is a very clean bird. Studies have shown
that each bird spends up to 3 hours per day preening
itself. Also they will bathe in water whenever they can.
Large flocks have been observed going into a pond for a
bath. They submerse, scrub, preen and shake and then
walk up on shore to spread their wings in the sun for
drying.
Turkey Vultures can locate carcasses by smell, a trait
that is unusual in the bird world. They also have keen
eyesight and search visually as well. Although we tend
to spot them most often eating carrion, up to 50 % of
their diet consists of vegetation. Lacking claw
strength, the TV cannot and does not kill and its beak
has neither the shape nor the strength to tear into a
fresh carcass. Cathartes aura, the TV’s scientific name
means “pacifier” or “cleanser” and the Cherokee Nation
calls this bird “peace eagle” because unlike the eagle,
which it resembles from a distance, it does not kill.
The TV’s digestive system has the unique ability to kill
any virus and bacteria in the food it eats. Tests
performed by the USDA during a hog cholera epidemic in
the south proved that the droppings and dry pellets that
are regurgitated are clean and disease free. The
pellets, which are smaller than a chicken egg, consist
of dried hair, bone material and vegetation and are
odorless. Animal food items in the pellets that were
examined included, shrews, moles, squirrels, gophers,
mice, rats, rabbits, birds, reptiles, insects, muskrats,
opossum, raccoon, skunk, badgers and coyotes. Imagine
the potential for the spread of disease (and the bad
smell!) if these carcasses had rotted on the ground
rather than being consumed and sterilized by the TV’s.
Because of this unique sterilization ability,
researchers are currently testing to see if digestion by
a TV can disinfect rodent carcasses carrying Hantavirus.
This research could be of great significance to human
medical research in this area and may also lead to vital
information for use in the event of biological warfare
or a worldwide epidemic.
I’m very grateful to have these resourceful birds
helping keep our earth clean and disease free, aren’t
you?
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