Anas americana vs American widgeon

Anas americana and American widgeon both are nouns.

Word	Noun	Adjective	Verb	Adverb
Anas americana	Yes	No	No	No
American widgeon	Yes	No	No	No

As nouns, Anas americana and American widgeon are synonyms defined as:

Anas americana and American widgeon: a widgeon the male of which has a white crown

Other synonyms of Anas americana include baldpate.

Anas americana (noun)	American widgeon (noun)
a widgeon the male of which has a white crown	a widgeon the male of which has a white crown