- Maui Nukupu'u or Hemignathus lucidus affinis extinct - 1995-1998
- Oahu Nukupu'u or Hemignathus lucides lucides extinct - 1837
- Kauai Nukupu'u or Hemignathus lucides hanapepe extinct - 1998
The Nukupu'u (Hemignathus lucidus) is a critically endangered species of Hawaiian honeycreeper in the Fringillidae family. There are no recent confirmed records and it may be extinct. It is (or possibly was) found in dense, wet `ohi`a forest and koa-`ohi`a forest at altitudes of 3300-6600 ft (1000-2000 m).
Males have yellow underparts and head. The upperparts are duller, darker and greenish. Females are overall duller, with most of the underparts whitish. The lores, eye-ring and long decurved bill are blackish. It is 5½ inches (14 cm) long.
The last sightings - both on Kauai and Maui - were in 1998, though it is possible some of the sighting in the 1990s actually involve the Kaua?i ?Amakihi. Later sightings remain unconfirmed. Recent surveys have failed to locate the species and the US Fish and Wildlife Service concluded that it in all probability is extinct or functionally extinct. BirdLife International (and thereby IUCN) have chosen to retain its status as critically endangered until additional surveys have confirmed its extinction beyond reasonable doubts. As several other Hawaiian honeycreeper, the decline of the Nukupu'u is connected to habitat loss (both due to man and hurricanes), introduced predators and disease-carrying mosquitoes.
The Nukupu'u is one of the species a project of the East Maui Watershed has been aimed at. Other birds from this area included the 'O'u and the Po?o-uli. The project involved fencing in the area and eradicating introduced predators. The entire project took out 22 feral cats, 209 feral pigs, 1,596 Polynesian rats, 1,205 black rats, and 1,948 common mice. On Kaua`i, comparable projects exists around the Koai`e Stream.