lesser scaup vs Aythya affinis

lesser scaup and Aythya affinis both are nouns.

Word	Noun	Adjective	Verb	Adverb
lesser scaup	Yes	No	No	No
Aythya affinis	Yes	No	No	No

As nouns, lesser scaup and Aythya affinis are synonyms defined as:

lesser scaup and Aythya affinis: common scaup of North America; males have purplish heads

Other synonyms of lesser scaup include lake duck, lesser scaup duck.

lesser scaup (noun)	Aythya affinis (noun)
common scaup of North America; males have purplish heads	common scaup of North America; males have purplish heads