bufflehead vs butterball

bufflehead and butterball both are nouns.

Word	Noun	Adjective	Verb	Adverb
bufflehead	Yes	No	No	No
butterball	Yes	No	No	No

As nouns, bufflehead and butterball are synonyms defined as:

bufflehead and butterball: small North American diving duck; males have bushy head plumage

Other synonyms of bufflehead include Bucephela albeola, dipper.

bufflehead (noun)	butterball (noun)
small North American diving duck; males have bushy head plumage	small North American diving duck; males have bushy head plumage
	a rotund individual