genus Cepphus vs bird genus

genus Cepphus and bird genus both are nouns.

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

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

genus Cepphus (noun)	bird genus (noun)
a genus of birds including: guillemots	a genus of birds