What is the only bird of prey known to hunt cooperatively in family groups?

Harris’s hawk is the only bird of prey widely known for routinely hunting cooperatively in family groups.

Harris’s hawks live in the arid and semi-arid regions of the southwestern United States, Mexico, Central America, and parts of South America. Unlike most solitary hawks, they often live and hunt in social groups that may include a breeding pair and their older offspring.

Groups can surround prey, flush animals from cover, or take turns pursuing them. Several birds may also perch together on a tall cactus or tree, creating the familiar “stacking” behavior. Cooperation is especially useful in open landscapes where prey can escape quickly into vegetation or burrows.

The species is sometimes called the bay-winged hawk or dusky hawk. It is also popular in falconry because of its intelligence, trainability, and social behavior. Although other raptors may occasionally cooperate, Harris’s hawk is the classic and most consistently documented example.