Flock (birds)

A flock is a gathering of individual birds to forage or travel collectively.^[1] Avian flocks are typically associated with migration. Flocking also offers foraging benefits and protection from predators, although flocking can have costs for individual members.^[2]

Flocks are often defined as groups consisting of individuals from the same species. However, mixed flocks consisting of two or more species are also common. Avian species that tend to flock together are typically similar in taxonomy and share morphological characteristics such as size and shape.^[3] Mixed flocks offer increased protection against predators, which is particularly important in closed habitats such as forests where early warning calls play a vital importance in the early recognition of danger. The result is the formation of many mixed-species feeding flocks.^[4]