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
ʻApapane Lānai. Apapane generally feed on nectar from flowers, preferably from the "ōhia lehua" ("Metrosideros polymorpha") tree. These birds are mainly found in "koa" ("Acacia koa") and "ōhia lehua" forests where the flower count is high. Although primarily nectarivorous, the diet of a grown apapane also includes a variety of insects like grasshoppers, caterpillars and bugs of all sorts. The breeding season is from January through July. The nest of the apapane is usually placed in the crown of a "ōhia lehua" ("Metrosideros polymorpha"); nests have been found in tree cavities and lava tubes as well as in the top of