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
Greater koa finch Greater koa finch The greater koa finch ("Rhodacanthis palmeri") was a species of finch in the Fringillidae family. It was found only in the Hawaiian Islands. It has been extinct since the late 19th century. The bird was about 7–8 in (18–20 cm) long when fully grown. It was the largest known honey-creeper, although its typical weight is unknown. The bird is sexually dimorphic; the male was brilliant scarlet-orange on head, neck, and breast, with lighter orange on its bottom, and olive brown with orange touches on back, wings, and tail; however, the female was brownish olive, and somewhat lighter