warbler vs singer

warbler and singer both are nouns.

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

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

Other hypernyms of warbler include vocaliser, vocalist, vocalizer.

warbler (noun)	singer (noun)
a small active songbird	a person who sings
a singer; usually a singer who adds embellishments to the song