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
Lesser koa finch Lesser koa finch The lesser koa finch ("Rhodacanthis flaviceps") is an extinct species of Hawaiian honeycreeper. The only specimens of the lesser koa finch ever caught were a family group with members of different ages and genders, ideal for study. The males were apparently golden-yellow with olive green on the breast and belly. The females were almost indistinguishable from the species' larger relative, the greater koa finch, other than the fact that the former were slightly darker in color. The juveniles were somewhat mottled on the belly, similar to the females. As its name suggests, the species as a whole