The ʻōʻū (pronounced [ˈʔoːʔuː]) (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.