bird of night vs owl

bird of night and owl both are nouns.

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

As nouns, bird of night and owl are synonyms defined as:

bird of night and owl: nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes

Other synonyms of bird of night include bird of Minerva, hooter.

bird of night (noun)	owl (noun)
nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes	nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes