genus Nestor vs bird genus

genus Nestor and bird genus both are nouns.

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

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

genus Nestor: a genus of Psittacidae containing two extant parrot species from New Zealand and two extinct parrot species from Norfolk Island, Australia and Chatham Island, New Zealand, respectively (Nestor)
bird genus: a genus of birds

genus Nestor (noun)	bird genus (noun)
a genus of Psittacidae containing two extant parrot species from New Zealand and two extinct parrot species from Norfolk Island, Australia and Chatham Island, New Zealand, respectively (Nestor)	a genus of birds