mallee fowl vs mound builder

mallee fowl and mound builder both are nouns.

Word	Noun	Adjective	Verb	Adverb
mallee fowl	Yes	No	No	No
mound builder	Yes	No	No	No

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

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

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

mallee fowl (noun)	mound builder (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