Campus pigeons, beware. Two raptors, identified by associate professor of ecology Stephen Pruett-Jones as Cooper’s hawks, have built a nest near Harper Memorial Library.

Colloquially known as “chicken hawks,” Cooper’s hawks—with wingspans of up to three feet—eat mainly smaller birds. They’re stealthy hunters, using trees or other cover to get close to their prey before attacking, swooping in to snatch a blue jay, robin, or pigeon.

In the United States the population of Cooper’s hawks has been increasing over the past 30 years. All they really need are tall trees for their nests and a ready supply of prey.

Pruett-Jones isn’t surprised these two hawks decided to make their home on the UChicago campus: “Cooper’s hawks are becoming very common in urban areas.”