sedge wren vs true warbler

sedge wren and true warbler both are nouns.

Word	Noun	Adjective	Verb	Adverb
sedge wren	Yes	No	No	No
true warbler	Yes	No	No	No

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

sedge wren: small European warbler that breeds among reeds and wedges and winters in Africa
true warbler: small active brownish or greyish Old World birds

Other hypernyms of sedge wren include Old World warbler.

sedge wren (noun)	true warbler (noun)
small European warbler that breeds among reeds and wedges and winters in Africa	small active brownish or greyish Old World birds
small American wren inhabiting wet sedgy meadows