Vultures are found across much of the United States, from the deserts of the Southwest to the forests of the Appalachian Mountains. The US is home to three species: the turkey vulture, black vulture, and California condor. Although all three feed on carrion, each has its own geographic range, behavior, and ecological role.
What are vultures?
Vultures are scavenging birds of prey that feed almost exclusively on carrion, the carcasses of dead animals. By rapidly removing carcasses from the landscape, vultures help reduce disease transmission and recycle nutrients back into ecosystems.
Convergent Evolution
Vultures in the United States all belong to the New World vulture or condor family. New World vultures evolved separately from Old World vultures and are adapted to the warm climates of the Americas. The scientific family name, Cathartidae, comes from a Greek word meaning “purifier,” a reference to the important role these birds play by removing carrion from the landscape.
The New World vulture family includes seven living species. In addition to the turkey vulture, black vulture, and California condor found in the United States, the family also includes the Lesser Yellow-headed Vulture, Greater Yellow-headed Vulture, King Vulture, and Andean Condor.
While vultures in the United States look similar to vultures found in Europe, Asia, and Africa, they are not related. Known as convergent evolution, these unrelated groups of vultures evolved similar features. New World vultures have bare heads and necks, an adaptation thought to improve hygiene by reducing the buildup of bacteria and decaying material while feeding.
In the United States, vultures are often called “buzzards,” although the term technically refers to several species of hawks in the genus Buteo, particularly those found in Europe.
A group of vultures in flight is known as a “kettle.” The term comes from the way the birds circle together in rising columns of warm air, resembling water swirling inside a boiling kettle. A group of vultures clustered on the ground or in trees is called a “committee.”
Turkey vultures
Turkey Vultures (Cathartes aura) are named for their red, featherless heads that bear resemblance to wild turkeys. Turkey vultures have a six-foot wingspan and weigh between 3.5 to 5 pounds.
The turkey vulture is the most widespread vulture in the United States. It breeds across most of the continental United States during spring and summer and remains year-round in the southern states.
Beyond the United States, Turkey Vultures range from southern Canada to the southern tip of South America. Birds nesting in the northern part of their range migrate south for the winter, while populations in warmer regions remain year-round.
Unlike most birds of prey, which rely primarily on exceptional eyesight, Turkey Vultures also possess a highly developed sense of smell that allows them to detect carrion from as far as a mile away. They have the most highly developed sense of smell of any bird, making them unique among avian scavengers. This remarkable adaptation allows them to occupy a wide range of habitats, including forests, deserts, grasslands, and suburban areas.
Turkey Vultures can detect the scent of ethyl mercaptan, a gas produced by decaying animals, even in minute quantities. This allows them to locate carrion hidden beneath forest canopies or otherwise concealed from view.
It is not uncommon to observe Turkey Vultures flying low over the landscape in a zigzag pattern as they follow the scent of a potential meal.
Black vultures
Black vultures (Coragyps atratus) are easily identified by their black plumage, short tails, and broad wings. They are found primarily in the southeastern United States, extending west into Texas, although their range has expanded steadily northward in recent decades.
Unlike Turkey Vultures, Black Vultures rely primarily on their exceptional eyesight rather than their sense of smell to locate carrion. They often soar high overhead, scanning the landscape for carcasses or watching for Turkey Vultures descending toward food.
Black Vultures are also more social and aggressive than Turkey Vultures. They frequently gather in large groups at communal roosts and feeding sites. Once a carcass has been found, Black Vultures often displace the smaller, less aggressive Turkey Vultures to gain access to the food.
Their expanding range has been linked to warmer winter temperatures, changing land use, and an increase in food sources associated with human activity, including roadkill and agricultural areas.
California condor
California condor (Gymnogyps californianus) is a critically endangered species and the largest land bird in North America. The California condor has become one of North America’s best-known wildlife conservation success stories.
The California condor is native to the Pacific Coast, particularly California and Arizona, with a smaller population reintroduced in Baja California, Mexico. With a wingspan of up to 9.5 feet (2.9 meters), it is the largest land bird in North America. The species once soared across much of the continent before habitat loss, lead poisoning, and other human activities drove it to the brink of extinction.
Thanks to decades of captive breeding and reintroduction efforts, California condor numbers have slowly increased. However, the species remains restricted mainly to the Grand Canyon area, the coastal mountains of central and southern California, and northern Baja California.
Geography affects the distribution of vultures in the United States
Several factors influence the distribution of vultures across the United States, including climate, food availability, habitat, and human activity. Although all three species are scavengers, they are not found in the same parts of the country. Differences in climate, habitat, migration, and food availability help explain why Turkey Vultures occur across most of North America, Black Vultures are concentrated in the eastern and southeastern United States, and California Condors remain restricted to a handful of reintroduced populations in the West.
Because vultures depend on carrion, they are most common in landscapes with abundant wildlife or where human activities provide reliable food sources, such as agricultural areas and highways.
Climate and weather also play a crucial role in vulture geography. For example, Turkey Vultures are partial migrators, shifting southward to avoid the harsh winters in the northern parts of their range. Moreover, the expansion of Black Vultures has been partly attributed to warmer winters in the northeastern US due to climate change.
Human activities have both reduced and expanded vulture ranges. Habitat loss, hunting, and lead poisoning have restricted species such as the California Condor. At the same time, agricultural landscapes, landfills, and roadkill have increased food availability for Black and Turkey Vultures, helping them expand into new areas.
References
Avery, M. L. (2004). Trends in North American vulture populations. In Proceedings of the Vertebrate Pest Conference (Vol. 21, No. 21). https://escholarship.org/uc/item/66q02691
Hill, J. E., Kellner, K. F., Kluever, B. M., Avery, M. L., Humphrey, J. S., Tillman, E. A., … & Belant, J. L. (2021). Landscape transformations produce favorable roosting conditions for turkey vultures and black vultures. Scientific Reports, 11(1), 14793. https://doi.org/10.1038/s41598-021-94045-3
