kagu, (Rhynochetus jubatus), nearly extinct and virtually flightless bird of New Caledonia, sole member of the family Rhynochetidae (order Gruiformes). About 55 cm (22 inches) long, it is a chunky bird with loose, gray plumage, including an erectile crest. The bill, legs, and eyes are reddish orange. In courtship the kagu dances with wings spread to show attractive spots of black, white, and rust. Its loud, piercing or rattling calls are heard mainly at night. It forages in forests for snails and insects. The introduction of dogs into New Caledonia was the main factor in its decline.