genus Corvus vs bird genus

genus Corvus and bird genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Corvus	Yes	No	No	No
bird genus	Yes	No	No	No

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

genus Corvus (noun)	bird genus (noun)
type genus of the Corvidae: crows and ravens	a genus of birds