Birds
Turkey Vulture
Cathartes aura · also called turkey buzzard, John crow
The turkey vulture is the most familiar vulture in the Americas — the dark, teetering bird seen circling over highways and fields. It is superbly adapted for a life spent finding and cleaning up the dead, including one sense that almost no other bird possesses.
Overview
Turkey vultures range across almost the entire Western Hemisphere, from Canada to the southern tip of South America, in open and semi-open country: grassland, farmland, desert, and the edges of forest. Northern birds are migratory, streaming south in large groups (“kettles”) each autumn, while those in warmer regions stay put year-round. They roost communally at night, often in bare trees or on structures, in groups that can number in the hundreds.
Finding food by smell
Most birds hunt or forage by sight. The turkey vulture adds smell, and it is central to how it lives. Its olfactory system is tuned to detect the gases of early decomposition, especially ethyl mercaptan, at very low concentrations, letting it locate a carcass it cannot see — under trees, in a ditch, behind a rock — from a great distance. It flies low, sampling the air, and drops onto the source. Black vultures, king vultures, and other scavengers often trail turkey vultures to find carcasses they could not smell themselves.
Built to soar and to scavenge
- Long, broad wings held in a shallow V let the turkey vulture ride thermals and updrafts for hours with almost no flapping, covering huge areas on very little energy.
- A bald head stays clean while feeding inside a body cavity.
- Extremely acidic stomach contents destroy the pathogens in rotting meat — anthrax, botulism, cholera — that would sicken most animals, so vultures both tolerate and remove disease reservoirs from the landscape.
- Weak feet reflect the fact that it never needs to catch or carry prey.
Defence and thermoregulation
A cornered or startled turkey vulture will regurgitate a foul, corrosive slurry of partly digested carrion, which deters predators and lightens the bird for a fast takeoff. On hot days it practises urohidrosis — excreting onto its own legs so that evaporation cools it, with the uric acid also killing bacteria picked up while walking through carcasses.
Reproduction and status
Turkey vultures make almost no nest, laying one to three eggs directly on the floor of a cave, cliff ledge, hollow log, or abandoned building. Both parents incubate and feed the chicks by regurgitation for around 10 to 11 weeks.
The species is listed as Least Concern, is very numerous, and has been expanding its range northward over recent decades, likely helped by warming winters and the abundance of roadkill. Unlike many Old World and some New World vultures, it is not in decline — though it remains vulnerable to poisoning from lead ammunition in carcasses and from poisoned baits set for other animals.
Turkey Vulture: common questions
Can turkey vultures really smell a dead animal from the air?
Yes, and it is unusual. Most birds have a poor sense of smell, but the turkey vulture has a large olfactory bulb and can detect ethyl mercaptan — a gas given off by early decay — in tiny concentrations, homing in on a carcass hidden under forest canopy from hundreds of metres up. Gas companies have used flocks of circling turkey vultures to locate leaks in pipelines carrying mercaptan-scented gas. The related black vulture cannot smell well and often follows turkey vultures to food.
Why do vultures have bald heads?
Feeding means pushing the head into carcasses, and bare skin is far easier to keep clean than feathers matted with blood and tissue, which would harbour bacteria. The bald head also helps with temperature control — the vulture can radiate heat from it when hot or tuck it into the shoulders when cold. In the turkey vulture the bare skin is red, giving the bird its name for the resemblance to a wild turkey's head.
Do turkey vultures kill anything?
Very rarely. They are built for scavenging, not hunting — their feet are relatively weak and flat, poor for gripping and killing prey, and their beaks, though hooked, are not powerful. They will take the occasional helpless newborn animal, stranded fish, or insects, and raid other birds' nests, but the overwhelming majority of their food is already dead. They perform an important sanitation service by removing carcasses quickly.
Is a turkey vulture the same as a buzzard?
In everyday American English "buzzard" usually means a turkey vulture, and "turkey buzzard" is a common name for it. But to ornithologists and in British usage, "buzzard" refers to a group of hawks in the genus Buteo. Turkey vultures are New World vultures, family Cathartidae, more closely related to storks and other New World vultures than to Old World vultures or to hawks.