Greater koa finch below. It had a thick black bill which allowed it to break open seed pods that were found in the trees. In historical times, its range was largely confined to the Kona District of the island of Hawaii, although it was observed in the Kīlauea area in 1895. It was much more widespread prior to the arrival of humans in Hawaii, and related species lived on other islands. In Kona, it co-occurred with the closely related lesser koa finch ("Rhodocanthis flaviceps"), and the Kona grosbeak. The lesser and greater koa finches were once thought by scientists to be the minimum
Koa people as the centre, they extended north as far as Kynuna. Their western boundary lay around Middleton Creek, wshile to the east, their frontier was at Winton and Sesbania. Their southern limits were around Cork. Neither circumcision nor subincision played any part in the Koa's initiatory rites into manhood. At least one Koa Bora ground, a gibber clearing threaded with portoluca, used to exist close to the homestead on Carisbrooke Station, southwest of Winton. Comparatively little is known of the Koa, and, in one modern tradition of whites in the area, they just 'melted away' when Europeans began to settle in