redstart vs American redstart

redstart and American redstart both are nouns.

Word	Noun	Adjective	Verb	Adverb
redstart	Yes	No	No	No
American redstart	Yes	No	No	No

As nouns, redstart and American redstart are synonyms defined as:

redstart and American redstart: flycatching warbler of eastern North America the male having bright orange on sides and wings and tail

Other synonyms of redstart include Setophaga ruticilla.

redstart (noun)	American redstart (noun)
European songbird with a reddish breast and tail; related to Old World robins	flycatching warbler of eastern North America the male having bright orange on sides and wings and tail
flycatching warbler of eastern North America the male having bright orange on sides and wings and tail