Though peregrine falcons, like other birds of prey, are considered to be near the top of the food chain, they are not completely free from predators. Adults may be killed by other, large birds of prey, such as great horned owls (Bubo virginianus), gyrfalcons (Falco rusticolus) and golden eagles (Aquila chrysaetos). Nestlings and fledglings may be taken by mammalian predators such as cats (Felis), bears (Ursus), wolverines (Gulo gulo), or foxes (Vulpes), particularly in nests that are closer to the ground. Humans take eggs to raise for falconry.
Peregrine falcons are aggressive in defense of their nests. They will attack birds and mammals that are much larger than themselves when defending their nest.