owl vs bird of prey

owl and bird of prey both are nouns.

Word	Noun	Adjective	Verb	Adverb
owl	Yes	No	No	No
bird of prey	Yes	No	No	No

As nouns, bird of prey is a hypernym of owl; that is, bird of prey is a word with a broader meaning than owl:

owl: nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes
bird of prey: any of numerous carnivorous birds that hunt and kill other animals

Other hypernyms of owl include raptor, raptorial bird.

owl (noun)	bird of prey (noun)
nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes	any of numerous carnivorous birds that hunt and kill other animals