The Sumatran Ground Cuckoo (Carpococcyx viridis) is a large, about 55 centimetres (22 in) long, long-tailed terrestrial species of cuckoo. It has a green upperparts plumage with black crown, green bill and legs, bluish green bare orbital skin and brown below. It was formerly considered conspecific with the Bornean Ground Cuckoo. An Indonesian endemic, the Sumatran Ground Cuckoo is distributed to rainforests of southern Sumatra. Before it was rediscovered and photographed in 1997 by Andjar Rafiastanto, this elusive species was known only from eight specimens.
Due to ongoing habitat loss and small population size, the Sumatran Ground Cuckoo is evaluated as Critically Endangered on the IUCN Red List of Threatened Species. In 2006, a camera-trap surveying for tigers close to Kerinci Seblat National Park took an image of the Sumatran Ground Cuckoo, only the second time it had been recorded in the last ninety years. The current population is estimated at less than 250. In 2007, its call was recorded for the first time according to New York-based Wildlife Conservation Society in a statement released February 26. The call, described as a two-syllable shriek, was recorded by WCS biologists after a trapper handed them a bird he had caught.