Aythya affinis vs lesser scaup duck

Aythya affinis and lesser scaup duck both are nouns.

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

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

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

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

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