scaup duck vs bluebill

scaup duck and bluebill both are nouns.

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

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

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

Other synonyms of scaup duck include broadbill, scaup.

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