When looking up at the sky, the sight of large birds circling effortlessly can spark curiosity. This aerial display, often associated with birds commonly called “buzzards,” is a common natural phenomenon. The graceful, spiraling movements prompt questions about why these birds engage in such distinct behavior.
Identifying Buzzards
In North America, the term “buzzard” typically refers to vultures, specifically the Turkey Vulture and the Black Vulture. These birds are distinctly different from the “buzzards” found in Europe, which are a type of hawk. North American vultures are large, dark-plumaged birds with broad wings, often seen soaring high above the landscape.
Turkey Vultures are identifiable by their reddish, featherless heads in adulthood, while Black Vultures have dark, featherless heads. Both species play a similar role in the ecosystem, despite some differences in their foraging strategies. Their flight patterns and physical adaptations are well-suited for their scavenging lifestyle.
Why the Sky Dance?
The circling behavior of these birds, often termed a “sky dance,” is primarily an efficient flight strategy. They utilize rising columns of warm air, known as thermals, to gain altitude without expending much energy. As the sun heats the ground, warm air rises, creating these invisible updrafts that vultures ride like an elevator. By circling within a thermal, they can continuously ascend with minimal flapping of their wings, conserving their energy for extended periods.
Once they reach a sufficient height, they can glide long distances, slowly descending until they find another thermal to catch. This “thermal soaring” allows them to cover vast territories while constantly scanning the terrain below. When multiple vultures gather in a single thermal, this collective circling is sometimes referred to as a “kettle.” This flight technique is not only for travel but also serves as a method for broad-area searching for food.
Finding the Feast
Vultures possess remarkable sensory abilities for locating carrion. Both Turkey and Black Vultures have keen eyesight, spotting potential food sources from great heights. They also observe other scavengers, including fellow vultures, to pinpoint a meal. Black Vultures often rely on following Turkey Vultures, as their sense of smell is less developed.
Turkey Vultures are unique among birds for their highly developed olfactory sense. They can detect the scent of ethyl mercaptan, a gas released during the early stages of decomposition, from up to a mile away. This acute sense enables them to locate hidden carcasses, even those obscured by dense foliage. This specialized adaptation helps them find food that other scavengers might miss.
Dispelling Myths
Many misconceptions surround circling “buzzards.” These birds are scavengers, feeding exclusively on dead animals, and do not pose a threat to live creatures or humans. They are not waiting for an animal to die as they circle; instead, they search for already deceased animals or use thermals for efficient flight. The notion of them as harbingers of death for living beings is inaccurate.
Vultures play a significant environmental role as nature’s cleanup crew. By consuming decaying carcasses, they help prevent the spread of diseases, such as anthrax, botulism, and rabies, by removing potential breeding grounds for harmful bacteria and viruses. Their digestive systems are adapted to neutralize pathogens, making them an important component of a healthy ecosystem.