genus Seiurus vs bird genus

genus Seiurus and bird genus both are nouns.

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

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

genus Seiurus (noun)	bird genus (noun)
ovenbirds and water thrushes	a genus of birds