wood warbler vs warbler

wood warbler and warbler both are nouns.

Word	Noun	Adjective	Verb	Adverb
wood warbler	Yes	No	No	No
warbler	Yes	No	No	No

As nouns, warbler is a hypernym of wood warbler; that is, warbler is a word with a broader meaning than wood warbler:

wood warbler: small bright-colored American songbird with a weak unmusical song
warbler: a small active songbird

wood warbler (noun)	warbler (noun)
small bright-colored American songbird with a weak unmusical song	a small active songbird
European woodland warbler with dull yellow plumage	a singer; usually a singer who adds embellishments to the song