songster vs vocaliser

songster and vocaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
songster	Yes	No	No	No
vocaliser	Yes	No	No	No

As nouns, vocaliser is a hypernym of songster; that is, vocaliser is a word with a broader meaning than songster:

Other hypernyms of songster include singer, vocalist, vocalizer.

songster (noun)	vocaliser (noun)
any bird having a musical call	a person who sings
a person who sings with skill	an organism that can utter vocal sounds
a composer of words or music for popular songs