The channel-billed cuckoo (Scythrops novaehollandiae) is a species of cuckoo in the family Cuculidae. It is monotypic within the genus Scythrops. The species is the largest brood parasite in the world, and the largest cuckoo. It is found in Australia, New Guinea and Indonesia; additionally, it is vagrant in New Caledonia and New Zealand. The species is migratory over part of its range. There are three subspecies, one migratory, the other two resident. The species is listed as least concern by the IUCN. Taxonomy Captain Arthur Phillip wrote of this (at the time) mysterious bird—calling it the 'psittaceous hornbill'—in his 1789 work The voyage of Governor Phillip to Botany Bay, consulting with ornithologist John Latham and deliberating that it had features of a parrot, hornbill or toucan, though conceding there were no toucans in the region. He gave it the name Scythrops novaehollandiae in 1790. Its generic name is derived from the Ancient Greek skuthro-/σκυθρο- 'angry' or 'sullen', and ops/ωψ 'face', 'eye' or 'countenance'. The specific epithet novaehollandiae means of New Holland, hence Australian. John White, the surgeon-general of the First Fleet to New South Wales, wrote A Journal of a Voyage to New South Wales in 1790, including this bird, which he termed 'anomalous hornbill". Three subspecies are recognised: the nominate Scythrops novaehollandiae novaehollandiae of Australia, New Guinea and the Moluccas, Scythrops novaehollandiae fordi in Sulawesi, and Scythrops novaehollandiae schoddei in the Bismarck Archipelago. The only member of the genus Scythrops, the species is most closely related to the long-tailed cuckoo (Urodynamis taitensis), which breeds in New Zealand and winters in the Pacific islands, according to Sorenson and Payne (2005). "Channel-billed cuckoo" has been designated as the official common name for the species by the International Ornithologists' Union (IOC). Latham gave it the name "channel-bill" after a groove in its upper mandible Description The world's largest cuckoo, the channel-billed cuckoo measures between long, with a wingspan, and weighing between . 24 adults were found to have averaged in body mass. According to a manual on avian body masses, another species of cuckoo, the buff-headed coucal, may have a mean body mass some 11% higher than the channel-billed cuckoo. The bill is bi-coloured, with a grey base becoming straw-coloured at the tip. The bill is large slightly curved and reminiscent of the bills of hornbills; in fact, the bird is sometimes erroneously referred to as a hornbill. The plumage of