For most raptors, hunting is not a team sport. Harris’ hawks, however, play the game a bit differently. Although a few other raptors are known to hunt cooperatively, Harris’ hawks are by far the most cooperative and coordinated in their hunting behavior. They use many strategies for hunting that rely on coordinated maneuvers by each member of the hunt. There are a number of proposed explanations for why these hawks have evolved to hunt this way: the challenge of navigating their rugged desert habitat, the ability to better defend their captured prey from other animals, or the fact that the jackrabbits they hunt are quite large relative to the size of an individual bird and are capable of killing a hawk if they can land a kick. This cooperative hunting seems to have shaped their social behavior as well. Harris’ hawks exhibit a behavior known as back-standing in which they perch on top of each other and form stacks up to 5 birds high! Much like their cooperative hunting, there is no clear answer yet for why they do this.
Sketch contributed by Christofer Brothers. Fact contributed by Adrian Perez.
Source: Bednarz, J.C., 1988. Cooperative hunting Harris’ hawks (Parabuteo unicinctus). Science, 239(4847), pp.1525-1527.