Phaethontidae vs bird family

Phaethontidae and bird family both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phaethontidae	Yes	No	No	No
bird family	Yes	No	No	No

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

Phaethontidae: tropicbirds
bird family: a family of warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings

Phaethontidae (noun)	bird family (noun)
tropicbirds	a family of warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings