Vultures circle because they ride rising warm air currents (thermals) to glide with little energy while scanning for carcasses.
Why
Vultures ride thermals, columns of rising warm air, to soar with little effort while searching for carrion.
Groups
A group in flight is a kettle. On the ground, a committee or wake.
How they find food
Turkey vultures have a strong sense of smell. Black vultures watch turkey vultures.
Do they circle dying animals
They circle to find food, not to wait for death.
Importance
Vultures clean up carcasses and limit disease.
Behavior
Vultures circle because they soar on rising columns of warm air called thermals, which let them glide for hours with little energy. From high up they scan a wide area for carcasses. Circling does not mean an animal below is dying, and it is a way to gain altitude and search for food.
- Turkey vultures have an unusually strong sense of smell and can detect ethyl mercaptan, a gas released by decaying meat. Black vultures rely more on sight and follow turkey vultures.
- The wingspan of a turkey vulture is about 1.7 to 2 m (5.5 to 6.5 feet), and a California condor can reach about 3 m (9.8 feet).
- A group of vultures on the ground is a “wake,” and in the air a “kettle.”
Importance
Vultures help ecosystems by quickly removing carcasses, limiting the spread of diseases such as anthrax and botulism. Their stomach acid is highly corrosive and kills many bacteria. In India, vulture populations dropped over 95 percent in the 1990s due to the veterinary drug diclofenac, which led to increases in feral dogs and rabies risks. Vultures are protected in the US under the Migratory Bird Treaty Act.
Behavior
Vultures circle to ride thermal updrafts while using their sense of sight and smell to locate carrion. Turkey vultures can smell ethyl mercaptan from decaying animals.
Importance
They clean ecosystems and reduce disease. Vulture populations have collapsed in India after diclofenac poisoning.
Soaring behavior
Vultures circle because they ride thermals, rising columns of warm air, to gain height with little energy. They rarely flap and glide in wide circles as they scan for carrion. Turkey vultures also use a sense of smell, one of few birds that do, to find dead animals, and black vultures follow them and use sight.
Why it matters
Wingspans reach 5 to 6 feet for turkey vultures and nearly 10 feet for the Andean condor. Circling does not always mean something is dying, as many are simply rising on a thermal. A group of circling vultures is called a kettle, and a group at a carcass is a wake. Vultures provide a sanitation service by eating carcasses, and their strong stomach acid kills many bacteria. They are protected under the Migratory Bird Treaty Act in the US.
Based on data from the Cornell Lab of Ornithology and the US Fish and Wildlife Service
