The red-billed ground cuckoo is long, about half of which is its tail. One male weighed . Adults have a heavy decurved red or orange bill tipped with green or yellow. Males and females of each subspecies have the same plumage. Adults of the nominate subspecies have a dark bluish black crown and shaggy crest with a purple gloss. Their nape and back are olive brown and the rump brown with a bronzy green gloss. Their tail is dark chestnut with an olive green gloss on the upperside of the central feathers. Their wings are mostly rufous; the outer
primaries are black with a violet blue gloss. Their face is ashy gray with red
lores, red skin around the eye, and bright blue skin behind the eye. Their throat is plain ashy gray, the breast ashy gray with faint black edges to the feathers and a black band below it. Their belly is buffy to light gray and the flanks and undertail
coverts dark brownish gray. Juveniles have brown upperparts without gloss, a blackish crest, purplish chestnut wings, black throat and chest, and a brown belly. Adults of subspecies
N. p. lepidophanes are similar, but with a clay-colored breast and belly rather than buffy to light gray. Their breast feathers appear more scaled as well. ==Distribution and habitat==