The Dark-billed Cuckoo has a long tail and a thick, curved bill. In the Galápagos it occurs from lowland sites to humid highlands and feeds mainly on insects.
The Galápagos account describes a gray-to-brown back, a gray head with black around the eye, and a long tail dotted with white. The underside is pale, and the bill is thick and curved.
In the Galápagos it feeds mainly on insects and also takes fruit. It makes an open cup nest, and both parents incubate; chicks are reported to leave the nest about two weeks before they can fly.
An extinction-risk assessment has not been added yet.