a story about the turkey vulture.
from The Birds of Texas
by John L. Tveten
The turkey vulture is one of three vulture species found in North America,
the other two being the black vulture and the California condor, an endangered
species. Both the turkey vulture and black vulture range widely across Texas,
although the black vulture is an infrequent visitor to the Panhandle and the northern
Trans-Pecos. Turkey vultures are found across the U.S. while black vultures occur
mainly in the south.
To most Texans, vultures are simply "buzzards," but that is an unfortunate
misnomer. The word "buzzard" was first applied to a common buteo hawk in Europe
and early settlers used the term to describe the vultures found in America. American
vultures, however, are a distinct family and differ from those in Europe, Asia
and Africa, which are more closely related to hawks and eagles.
American vultures have small, unfeathered heads and hooded beaks, both of
which are useful adaptations for feeding on the carrion that makes up a major
portion of their diets. Their talons are weak and poorly suited for grasping the
living prey taken by most hawks and their close relatives. Vultures are gregarious
birds, feeding together and assembling in large flocks to roost at night. During
the nesting season, however, they become solitary. They do not build nest structures,
but instead lay their eggs in sheltered nooks on rocky ledges, in the hollow trees,
or even in deserted buildings.
The turkey vulture is a large, sleek black bird with a naked red head, white
beak, long tail and six-foot wing span. Its ratio of body weight to wing area
makes it a near perfect sailplane. The turkey vulture uses thermals to carry it
aloft, where it soars high above the ground, sweeping in wide circles within the
bounds of the rising columns of warm ascending air. Its slender wings appear two-toned
from below, the steel-gray flight feathers contrasting with black wing linings.
Its cousin, the black vulture, is smaller and has a short tail, black head
and a wing span less than five feet. Its shorter, broader wings have white patches
near the tips. The black vulture's build makes it less efficient in soaring, so
it will alternate rapid flapping with short glides. Unlike the turkey vulture,
which feeds mostly on carrion and refuse, the black vulture will prey on small
mammals, reptiles and young birds.
Turkey vultures breed throughout Texas but typically migrate south in the
winter. Although some stay year-round, most spend the winter in Central America.
Black vultures also migrate and may travel as far south as Brazil. Both are common
in open country, woodlands, fields and farms, with black vultures more likely
to be found near human settlements and garbage dumps.
Do vultures find food by sight or smell?
Ornithologists have long wondered whether vultures locate their decaying food
by sight or smell. Birds are particularly attuned to sight and sound, but most
display little sense of smell. The turkey vulture seems to be an exception. It
has a particularly well-developed olfactory lobe in its brain and experiments
indicate a keen sense of smell. Even so, it seems unlikely that odor can play
a major role in detecting carrion from the altitude at which the vulture often
forages. In that case, it seems more likely that one vulture spots a carcass and
others within sight are guided by its actions.