Gavidae vs bird family

Gavidae and bird family both are nouns.

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

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

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

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