Turkey Vultures - Nature's Sanitary Engineers

I Wonder Why Vultures Are Bald: and Other Questions About Birds
Turkey vultures: nature's sanitary engineers
Bay Naturalist / By Kathy Reshetiloff - Bay Journal

Turkey vultures. They're hard to admire. After all, they eat carrion, defend their nests by regurgitating and excrete on themselves. Still, they perform an important, yet thankless, function. Turkey vultures help to rid the landscape of road kill and other carcasses. This is even reflected in their scientific name, Cathartes aura. Cathartes from the Greek word, katharsis, meaning to purge or cleanse.

Turkey vultures are common from southern Canada, throughout most of the United States and into South America. Northern birds are migratory, and leave colder areas in September and October for warmer climates. Some turkey vultures migrate in flocks, while others join up en route south.

The turkey vulture is a brownish black bird with two-tone, black wings and a naked, red head. A large bird, the turkey vulture has a wingspan of nearly 6 feet. Once in the air, the turkey vulture is quite graceful, soaring for hours on updrafts and rising columns of warm air called thermals. In flight, a turkey vulture holds its wings extended into a V-shape, lightly rocking from side to side. Turkey vultures are able to stay within the thermals by flying in tight circles.

Their diet consists almost entirely of fresh to putrid carrion, although they will occasionally eat decaying vegetation, insects or fish. Efficient scavengers, turkey vultures quickly dispose of carcasses. They are able to consume the bodies of animals that have died of illness or infection without being adversely affected.

Turkey vultures are most likely to be found soaring over open or semi-open country, including fields, lightly wooded areas, deserts and foothills. They often congregate in areas known as roosts. They rest and sun themselves in the largest trees. Late risers, turkey vultures wait for the sun to warm them. They pose with wings slightly drooped, which is known as a spread wing posture. This helps to dry their wings and regulate their body temperature. Wing spreading in the morning absorbs solar energy, passively raising the bird's temperature to its daytime level.

As they have no syrinx or voice box, turkey vultures cannot sing like other birds. Instead, they hiss, grunt and huff.

Now for some of their unsavory habits. Yes, if threatened or disturbed they will regurgitate. There are several explanations as to why they do this. Some believe that other carnivores will consume the regurgitated material and leave the turkey vulture alone. Or, it may serve to distract a potential predator. Most believe that it is simply a defensive reaction caused by fright.

Turkey vultures have one more bad habit; they excrete down their legs. There are two theories as to why they do this. One is that their excrement contains so much ammonium that it helps to kill bacteria. Another theory is that they do it to cool themselves. Despite these characteristics, they do have redeeming qualities. Pairs are monogamous, and both parents incubate the eggs, as well as feed and care for the young. Nest sites consist of little or no nest at all. Eggs are laid on debris inside a hollow tree or log, in crevices on cliffs, and in caves, dense thickets or old buildings.

Usually, two whitish eggs, blotched with brown and lavender, are laid. Incubation lasts 34-41 days. Young are born with a coat of down and open eyes but must be fed by their parents' regurgitation. If the nest is disturbed, parents will protect it by violently vomiting. Immature turkey vultures look like their parents except for their black heads and beaks.

The young are able to fly at about 9-10 weeks old. Their beaks turn to adult white or ivory by the time they are 4 years old.

Though they may not be on your list of favorite birds, turkey vultures do help to recycle carcasses quickly. With the increase in development, there is undoubtedly more road kill. Scavengers like turkey vultures keep the surrounding environment clear of unsightly and decaying animal bodies.

Without them, every day would be like a garbage strike. So remember this the next time you look up and see one circling gracefully overhead.

Kathryn Reshetiloff is with the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office in Annapolis.

Turkey vultures: nature's sanitary engineers
Article - Bay Journal
Jan,Feb 1998

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