mound bird vs gallinacean

mound bird and gallinacean both are nouns.

Word	Noun	Adjective	Verb	Adverb
mound bird	Yes	No	No	No
gallinacean	Yes	No	No	No

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

mound bird: large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs
gallinacean: heavy-bodied largely ground-feeding domestic or game birds

Other hypernyms of mound bird include gallinaceous bird.

mound bird (noun)	gallinacean (noun)
large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs	heavy-bodied largely ground-feeding domestic or game birds