scaup duck vs scaup

scaup duck and scaup both are nouns.

Word	Noun	Adjective	Verb	Adverb
scaup duck	Yes	No	No	No
scaup	Yes	No	No	No

As nouns, scaup duck and scaup are synonyms defined as:

scaup duck and scaup: diving ducks of North America having a bluish-grey bill

Other synonyms of scaup duck include bluebill, broadbill.

scaup duck (noun)	scaup (noun)
diving ducks of North America having a bluish-grey bill	diving ducks of North America having a bluish-grey bill