A bird of prey is just a family of birds that mainly hunt while flying for their food. As usual, there are ofcourse exceptions; some of the B.O.P. habitually look for prey from a perch, just like owls (also birds of prey). One kite lives exclusively on snails.
We have a blackbird and his missus who reappear every year. A few years back there was a tremendous kerfuffle, and they shot through the shrubbery either side of a bluetit, and the smaller one plummeted to earth, very dead. Mrs B was brooding, but can't figure what offence had merited capital punishment.