bluebill vs scaup duck

bluebill and scaup duck both are nouns.

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

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

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

Other synonyms of bluebill include broadbill, scaup.

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