sawbill vs sheldrake

sawbill and sheldrake both are nouns.

Word	Noun	Adjective	Verb	Adverb
sawbill	Yes	No	No	No
sheldrake	Yes	No	No	No

As nouns, sawbill and sheldrake are synonyms defined as:

sawbill and sheldrake: large crested fish-eating diving duck having a slender hooked bill with serrated edges

Other synonyms of sawbill include fish duck, merganser.

sawbill (noun)	sheldrake (noun)
large crested fish-eating diving duck having a slender hooked bill with serrated edges	Old World gooselike duck slightly larger than a mallard with variegated mostly black-and-white plumage and a red bill
	large crested fish-eating diving duck having a slender hooked bill with serrated edges