Red-billed Ground-Cuckoo

The red-billed ground cuckoo is 43 to 55 cm (17 to 22 in) long, about half of which is its tail. One male weighed 330 g (12 oz). 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.

The red-billed ground cuckoo is a bird of the upper Amazon basin. The nominate subspecies is found in eastern Peru and western Brazil north of the Amazon River. A sight record in Ecuador leads the South American Classification Committee of the American Ornithological Society to treat it as hypothetical in that country. That committee has not evaluated another sight record from Colombia. Subspecies N. p. lepidophanes is also found in eastern Peru and western Brazil but south of the Amazon. The species inhabits moist lowland evergreen forest, usually that on somewhat hilly terrain with well-drained soil at elevations up to 700 m (2,300 ft).

The red-billed ground cuckoo's diet has not been extensively studied but is mostly insects. It also includes other arthropods; small vertebrates like lizards, amphibians, and small birds; and sometimes fruits. It follows army ant swarms and peccaries to catch prey fleeing from them, and monkey troops to feed on fallen fruits.