brush turkey vs mound bird

brush turkey and mound bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
brush turkey	Yes	No	No	No
mound bird	Yes	No	No	No

As nouns, mound bird is a hypernym of brush turkey; that is, mound bird is a word with a broader meaning than brush turkey:

brush turkey: black megapode of wooded regions of Australia and New Guinea
mound bird: large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs

Other hypernyms of brush turkey include megapode, mound-bird, mound builder, scrub fowl.

brush turkey (noun)	mound bird (noun)
black megapode of wooded regions of Australia and New Guinea	large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs