Siivikehä

Siivikehä is a Finnish term that translates to "wing-circle" or "flight ring." It refers to a phenomenon observed in avian behavior, particularly in birds of prey. This behavior involves a group of birds, often of the same or different species, circling in the sky. While often associated with soaring on thermals, the specific context of a siivikehä can indicate various things depending on the circumstances.

A common reason for a siivikehä is the presence of a food source. If a carcass is found, multiple birds may gather to feed, and their circling can be a prelude to landing or a way to establish a pecking order. In other instances, a siivikehä can be a sign of a predator, such as a larger bird of prey, that has attracted the attention of smaller birds. The smaller birds may mob the predator, circling and harassing it in an attempt to drive it away.

Sometimes, a siivikehä can also be a social gathering or a territorial display. Birds might circle together for mating rituals or to reassert their dominance over an area. The altitude and speed of the circling, as well as the species involved, can provide clues to ornithologists about the underlying cause of the siivikehä. Observing these aerial congregations is a way to understand the complex interactions within avian communities and their responses to environmental factors.