brush turkey vs mound builder

brush turkey and mound builder both are nouns.

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

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

brush turkey: black megapode of wooded regions of Australia and New Guinea
mound builder: 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 bird, scrub fowl.

brush turkey (noun)	mound builder (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