1.  mound builder(n = noun.person) - prehistoric Amerindians who built altar mounds;
is a kind of primitive, primitive person

2.  mound builder(n = noun.animal) megapode, mound bird, mound-bird, scrub fowl - large-footed short-winged birds of Australasia; build mounds of decaying vegetation to incubate eggs;
is a kind of gallinacean, gallinaceous bird
is a member of family megapodiidae, megapodiidae
has particulars: leipoa, leipoa ocellata, lowan, mallee fowl, alectura lathami, brush turkey, macrocephalon maleo, maleo

builder, burial mound, cannibal mound, detergent builder, grave mound, morale builder, mound, mound bird, mound over, muscle builder, pitcher's mound, road builder, ship builder