mallee fowl vs megapode

mallee fowl and megapode both are nouns.

Word	Noun	Adjective	Verb	Adverb
mallee fowl	Yes	No	No	No
megapode	Yes	No	No	No

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

mallee fowl: Australian mound bird; incubates eggs naturally in sandy mounds
megapode: large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs

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

mallee fowl (noun)	megapode (noun)
Australian mound bird; incubates eggs naturally in sandy mounds	large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs