Even though Peregrine falcons are the top predators, the adult falcons are still vulnerable to some of the larger avian hunters. These predators include Gyrfalcons, great horned owls and eagles.
But the juveniles and hatchlings of peregrine falcons are at the mercy of much larger and great number of predators like other peregrines.
Some of the mammalian predators often prey on the ground nests of peregrine falcons. These mammals include cats, foxes, bears, wolverines and wolves.
White, Clayton M., Nancy J. Clum, Tom J. Cade and W. Grainger Hunt. 2002. Peregrine Falcon (Falco peregrinus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.660