The black stilt (Himantopus novaezelandiae) or kakī (Māori) is a wading bird found in New Zealand. It is one of the world's rarest birds, with 169 adults surviving in the wild as of May 2020. Adult kakī have distinctive black plumage, long pink legs, and a long thin black bill. Black stilts largely breed in the Mackenzie Basin in the South Island, and are threatened by introduced feral cats, ferrets, and hedgehogs as well as habitat degradation from hydroelectric dams, agriculture, and invasive weeds. Black stilts are a medium-sized (220 g) wader with extremely long pink legs, red eyes, distinctively black plumage, and a long slender black bill. Juveniles have a white breast, neck and head, with a black patch around the eyes, and black belly feathers that distinguish them from pied stilts. Black adult plumage appears in their first or second year. Black plumage may be an adaptation to "absorb heat better in the cold, windswept habitat of glacial riverbeds and lakeshores". Hybrids between black and pied stilts are very variable in their plumage, but usually have black breast feathers, which pied stilts never do.