Peregrine falcons are a top predator, but they are vulnerable to larger birds that may prey on them. Young peregrine falcons are vulnerable to mammals that may climb into the nest if it is too low to the ground.
The great horned owl, gyrfalcon and golden eagle are all larger than the peregrine falcon and can kill an adult peregrine falcon. Foxes, cats, wolverines and bears are able to climb trees and often go after fledgling peregrine falcons still in their nests. They do not get their prey easily, since peregrine falcons are known to be very defensive around their nests.