Critically Endangered

Formerly common on all islands, `O`u are now extinct on O`ahu, Maui, Moloka`i, and Lana`i. Small populations of this rare bird remain in the Alaka`i Swamp of Kaua`i and along the windward coast of the island of Hawai`i.

Distribution: `O`u dwell in the central and southeast areas of the Alaka`i Swamp of Kaua`i and midelevation `ohi`a forests in the windward districts on Hawai`i.

Description: Males have a bright yellow head with a dark green back and lighter olive-green underparts. Females and juveniles are duller with an olive-green head. Both sexes are 7 inches in length and have a parrot-like, pale pinkish bill with the upper mandible curving over the lower.

Voice: The call of the `O`u is an ascending or descending whistle, which may break into a sweet and distinct song. The canary-like song has three or four penetrating whistled notes and a trill.

Nesting: Breeding biology is unknown, although juveniles have been seen in June, and from the end of March to mid-May females have been noted to have greatly enlarged ovaries.

Diet: `O`u feed on fruits of lobellia, guava, and particularly those of le`ie. Buds and blossoms of `ohi`a make up an additional part of their diet as well as insects, particularly caterpillars which are fed to young `O`u.

Conservation Note: The `O`u is the rarest of Hawaiian honeycreepers on Hawai`i, and among the rarest of all forest birds dwelling in the Alaka`i Swamp of Kaua`i. Like other native forest birds, `O`u now occupy a small fraction of their former range. Their drastic decline began with the first clearing of native forest habitat for agriculture and continues today with the myriad disruptions caused by grazing feral animals, introduced plants, and avian diseases.

`O`u have been known to descend into lower elevation forests to obtain the fruits of guava and mountain apples. This habit may have contributed to their population decline by exposing them to mosquitoes and the avian diseases they carry. The grazing activities of feral animals on Kaua`i continues to pose a threat to `O`u habitat, although cattle have been eliminated from the Alaka`i and hunting helps to control habitat damage by goats and pigs.

It is important that the mid-elevation `ohi`a forests providing refuge for the `O`u on the island of Hawai`i be preserved and managed if this scarce and beautiful bird is to survive. Management of the forests will include: the control of predators and feral grazing mammals, reduction of mosquito breeding sites, and control of introduced plants, such as banana poka which is presently choking out much of the native vegetation. The restoration of native forests in existing pastures may also serve to provide much needed habitat for the widely scattered population of the endangered `O`u.