Aythya vs bird genus

Aythya and bird genus both are nouns.

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

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

Aythya (noun)	bird genus (noun)
canvasback, redhead, pochard, etc.	a genus of birds