songster vs oscine bird

songster and oscine bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
songster	Yes	No	No	No
oscine bird	Yes	No	No	No

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

Other hypernyms of songster include oscine.

songster (noun)	oscine bird (noun)
any bird having a musical call	passerine bird having specialized vocal apparatus
a person who sings with skill
a composer of words or music for popular songs