Regulus vs bird genus

Regulus and bird genus both are nouns.

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

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

Regulus (noun)	bird genus (noun)
a genus of birds of the family Sylviidae including kinglets	a genus of birds
the brightest star in Leo