Turkey vultures (Cathartes aura) are somewhat homely looking birds with small, featherless red heads and huge wing spans of 63-72 inches. Because they lack a syrinx, the vocal organ of birds, a turkey vulture's vocal abilities are limited to a series of grunts and hisses. On average, these birds weigh approximately 4 lbs. They belong to the Cathartidae family which includes storks and California condors.
A turkey vulture can be readily identified by its profile. When perched, this bird holds its wings in a slight V position. During flight, turkey vultures rarely flap their wings and can glide through the sky for up to six hours without a single flap. They accomplish this by soaring very high in the air to catch wind currents. Pilots have reported observing turkey vultures riding on air currents as high as 20,000 ft.
These vultures are the only scavenger birds that cannot kill their prey. In comparison to most other birds, the turkey vulture has a very highly developed sense of smell that helps it locate the carrion (dead animals) on which it feeds. They eat a varied diet including small mammals, road kill, and larger animals such as dead sheep and cows. They will also eat certain fruits and insects. Turkey vultures can devour a large quantity of food and then easily go for several days without eating again. Like storks, turkey vultures defecate on their legs as a means of sanitizing their food and cooling themselves with the evaporating urine and feces. They excrete uric acid in large quantities. This chemical functions to kill any bacteria ingested as the vulture feeds. Turkey vultures are not often bothered by chemical poisons that have been eaten by the carrion they consume.
The turkey vulture builds its nest in the cavities of trees and logs. Nesting trees typically range in diameter from 36 inches to 65 inches in circumference at the breast height of the birds. The cavities are vertical tubes in the tree trunks that can drop down as much as 13 ft. from the entrance to the bottom. This type of nest is very different from the open cup nests of other large birds such as ospreys and eagles. Turkey vulture nests are often used by generations of the birds. After hatching, the parents enter the cavity five or six times daily to feed the young. How these large birds maneuver so easily within the tree cavity is one of nature's conundrums.
Turkey vultures are highly social birds that prefer to roost in large colonies in the company of their own species and are often spotted flocking together on utility towers, roofs, tall buildings and in the tops of trees. They possess no syrinx, the vocal organ of birds, and therefore cannot sing or vocalize in the way most birds typically do. They communicate with each other by using a series of hisses and grunts. They can be found throughout the entire United States most of the year and are found year around in warmer areas. Vultures in cold climates generally spend winters in South America. Turkey vultures are protected by the Migratory Bird Treaty Act of 1918. This is important to know in case control measures become necessary.
The term for groups of vultures is a kettle. As they catch thermal updrafts high in the air, they resemble a swirling pot of boiling water reminiscent of a tea kettle. When I spot turkey vultures soaring overhead at my house, they appear to float effortlessly through the sky creating elegant, graceful silhouettes. They have been seen by aircraft pilots as high as 20,000 ft.
As part of nature's clean up crew. turkey vultures display some interesting traits. Homely, yes, but with an important ecological job. Because of the extremely corrosive nature of their digestive juices, they are not affected by toxins such as rabies, anthrax, bubonic plague or distemper and can ingest diseased animals without harming themselves. In addition, their bald heads make it possible for them to access filthy locations without contaminants sticking to their feathers. What does stick to their heads is easily neutralized by rain and sun.
Turkey vultures possess a way to disinfect their feet as well. They defecate on their legs releasing such strong amounts of uric acid that the chemical kills whatever it touches. This helps keep the birds healthy no matter where they land or what they eat. A vulture's feet are similar to chicken feet which have talons that are not sharp or strong enough to pick up or hold prey. A turkey vulture can only use its feet for walking.
These birds seem almost indestructible. However, they do have one deadly enemy: lead. When a turkey vulture ingests any type of lead such as shotgun pellets, the bird's highly corrosive digestive juices dissolve the lead which is then absorbed by its body. This most often results in the death of the bird.
Some people describe these birds as ugly. Beauty is always in the eye of the beholder. As part of nature's clean-up crew, they have an important ecological job to perform. It's a job they are exceptionally well-equipped to do.
References: http://dnr.wi.gov/org/caer/ce/eek/critter/bird/turkeyVulture.htm; Audubon Guide to North American Birds (http://www.audubon.org/field-guide/bird/turkey-vulture); http://pestproducts.com/turkey-vulture.htm; top photos from Morguefile, bottom photos are mine