brush turkey vs megapode

brush turkey and megapode both are nouns.

Word	Noun	Adjective	Verb	Adverb
brush turkey	Yes	No	No	No
megapode	Yes	No	No	No

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

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

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

brush turkey (noun)	megapode (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