genus Atrichornis vs bird genus

genus Atrichornis and bird genus both are nouns.

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

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

genus Atrichornis (noun)	bird genus (noun)
type genus of the Atrichornithidae	a genus of birds