Rheidae vs bird family

Rheidae and bird family both are nouns.

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

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

Rheidae: a family of birds coextensive with the order Rheiformes
bird family: a family of warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings

Rheidae (noun)	bird family (noun)
a family of birds coextensive with the order Rheiformes	a family of warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings