Why do some pigeons feed in flocks?

The habit of feeding in flocks among pigeons is primarily believed to assist the birds in locating food, rather than serving as an antipredator device.1

When feeding on the ground, pigeons must look downward for much of the time, which leaves them vulnerable to predators. While some might assume flocking is a defensive strategy, the behavior is more closely linked to the efficiency of finding resources. In some cases, such as with fruit pigeons in tropical forests where trees with ripe fruit occur sporadically, moving in flocks allows the birds to more effectively seek out food across large areas.12

A consequence of this social feeding behavior is the development of a peck order, or social hierarchy, within the flock. In competitive situations, dominant individuals may supplant submissive ones, which can result in the latter receiving less food.1