Vulture Roosting Behaviors
By Phil Miller, Wildlife Biologist, Wildlife and Freshwater Fisheries Division
Vultures are some of the most common species of birds found in Alabama and throughout the southeast. Vultures commonly seen in the Southeast are classified as one of two species, the turkey vulture (Cathartes aura) or the black vulture (Coragyps atratus). The common name for these two species is derived from their appearance. The turkey vulture has a red, wrinkled head and a dark body that resembles a wild turkey from a distance. The black vulture, with its head and neck being a dark to light gray and furrowed with wrinkles, has a black appearance.
These two species of birds are commonly seen circling in the sky or standing along the roadside eating the carcass of dead animals. Known as “scavengers of the skies,” vultures were once hunted in large numbers because of the belief that they carry diseases. But over time, they have come to be seen as a beneficial asset by cleaning up the remains of dead animals. Today, most view the vulture as one of nature’s most efficient, natural recyclers.
At the end of a long day of feeding and searching for food, vultures begin to move back to their roosting sites. Both species form large communal roosts, with some containing over a thousand birds. Vultures will usually return to the same roost each night and generally roost on the same branch as previous nights. These roosts may or may not be made up of family members. Observations of vulture roosts showed both species will occupy the same roosts and use them year after year. Some of these roosts are believed to be over 100 years old and are shared by parents and grandparents.
Common roosting sites preferred by vultures are power lines, radio towers, tall trees, or old buildings. These roosts create a foul smell and may seem unsanitary to the human eye, but due to the unique digestive system of vultures any bacteria or disease they may ingest is killed. Their droppings and pellets (undigested bones and fur) are considered disease free.
During the early morning, vultures can be observed at their roosting site with their wings stretched outward. This wing stretch allows the birds to use the sun and early morning warmth to repair damaged feathers, raise body temperature and dry flight feathers after wet weather.
Once the morning temperature warms up and thermals begin to form, turkey vultures begin to leave their roost individually. Most black vultures wait about an hour longer than the turkey vulture before leaving their roost. The late departure of black vultures is due to having a heavier wing load and waiting for stronger thermals to stay aloft. When the thermals are right, black vultures begin to leave their roost in groups.
Vultures may seem unattractive or disgusting, but they play an important role in the animal world. Nature uses these birds to help clean up the environment of decaying animals. This clean-up crew provides a service that could prevent the spread of certain diseases.