scaup vs bluebill

scaup and bluebill both are nouns.

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

As nouns, scaup and bluebill are synonyms defined as:

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

Other synonyms of scaup include broadbill, scaup duck.

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