The ʻōʻū (Psittirostra psittacea) is a species of Hawaiian honeycreeper endemic to the Hawaiian islands. It has a dark green back and olive green underparts; males have a yellow head while females have a green head. Its unusual beak seems to be adapted to feeding on the fruits of Freycinetia arborea. It has a strong flight which it uses to fly considerable distances in search of this Hawaiian endemic vine, but will eat other fruits, buds, flowers and insects.
Although formerly widespread and present throughout the island group, numbers declined dramatically during the twentieth century. The bird is listed by the International Union for Conservation of Nature as being Critically Endangered, but there are no recent records and it may be extinct. The last recorded sighting was in 1989.