Oʻahu nukupuʻu bill to pluck insects found underneath tree bark, the Oahu nukupuu fed on insects on flowering trees such as the koa ("Acacia koa") and ohia ("Metrosideros polymorpha"). These trees attract a large amount of insects due to their nectar-filled flowers. The Oahu nukupuu fed on koa in high elevation forests and fed on ohia in low elevations. The species was believed to have vanished as the spread of disease occurred, killing off nukupuu populations across the islands. In order to control the rat population in the sugar cane fields, mongooses were introduced to Hawaii and were suspected to be predators
Scissor-billed koa finch Kanaloa" ("Kanaloa kahoolawensis") and "koaia" ("Acacia koaia") were probably important food sources, and it may have eaten caterpillars and "aalii" ("Dodonaea viscosa") berries. Due to its early extinction, very little is known about this species. It is only known from fossil remains. Other Hawaiian honeycreepers are known to have become extinct or very rare due to habitat loss, introduced predators and avian diseases. It is possible the extinction of the scissor-billed koa finch also involved these factors. Scissor-billed koa finch The scissor-billed koa finch, ("Rhodacanthis forfex") or scissor finch is an extinct species of Hawaiian honeycreeper. Of the four species