Large birds circling high in the sky, often called buzzards, do so for specific reasons tied to their survival and flight adaptations. This aerial display is a calculated strategy that allows them to efficiently navigate their environment.
Riding the Air
A primary reason buzzards circle is to conserve energy by riding air currents. They utilize “thermals,” which are columns of warm air rising from the ground. As the sun heats the Earth’s surface, air above warmer spots becomes less dense and ascends. Buzzards locate these invisible columns and circle within them, gaining altitude with minimal effort.
Thermal soaring allows them to gain altitude without extensive wing flapping. They glide from one thermal to another, covering vast distances while expending very little energy. Their broad wings and low body-to-wing ratio are well-suited for this soaring, enabling them to stay aloft for hours. This energy-efficient flight is an important adaptation, allowing them to cover large territories in search of food.
Scanning for Food
Circling also serves an important purpose in the buzzard’s search for food. While soaring, these birds scan the landscape below for carrion (decaying flesh). Their exceptional eyesight allows them to spot potential food sources from great heights. Black Vultures, for instance, primarily rely on their vision to locate food, often flying at higher altitudes for a better vantage point.
Some species, such as the Turkey Vulture, also possess a highly developed sense of smell, enabling them to detect gases released by decomposing carcasses from long distances. When a Turkey Vulture detects a scent, it may circle downwards, guiding other vultures, including those with a poorer sense of smell like the Black Vulture, to the food source. This combined use of sight and, for some, smell, makes their circling an effective foraging strategy, contributing to their role as nature’s clean-up crew.
Who Are These Circling Birds?
The birds commonly referred to as “buzzards” vary by region. In North America, the term typically refers to vultures, primarily the Turkey Vulture and the Black Vulture. In Europe, “buzzard” often denotes the Common Buzzard, a bird of prey that primarily hunts small mammals but will also scavenge carrion.
These birds have distinct appearances in flight. The Turkey Vulture is characterized by its large size, dark plumage, and a distinctive V-shaped wing profile (dihedral) while soaring, often appearing to teeter unsteadily. Black Vultures are entirely black with shorter tails and broad wings held flat during flight, punctuated by quick wingbeats. The Common Buzzard is a broad-winged raptor with varying brown plumage, often holding its wings in a shallow V-shape when soaring.