Endemic to western Amazonia, where it is known from sight records in southeast Colombia and eastern Ecuador, as well as from northeast Peru and western Brazil east to the Rio Negro, this ground-cuckoo is, like the entire genus Neomorphus, poorly known and rarely encountered. Compared to the Rufous-vented Ground-Cuckoo (Neomorphus geoffroyi), with which the Red-billed Ground-Cuckoo may yet prove to be sympatric in some areas of southern Colombia and northern Peru, the present species is best distinguished by the red bill, all-black crown and crest, and cinnamon-buff belly. It is confined to lowland forests below 700 m, where the species is most likely to be found following an army ant swarm or group of peccaries, seizing fleeing insects, although plant matter has also been reported in stomach contents. Its vocalisations are poorly known, although it bill-snaps in common with other ground-cuckoos, and the Red-billed Ground-Cuckoo is also reported to making a guttural humming noise or gruff hooting, somewhat like the voice of some curassows (Mitu). The species’ breeding behavior is to all intents and purposes unknown, although there is a very old report of a pair tending a nest with eggs.