The apapane, a crimson-colored bird, is a quintessential Hawaiian honeycreeper and is easily seen as it feeds on the nectar of the red flowers on the ohia tree. Its song, mostly in the realm of repeated trills, is punctuated by whistles and bell-like notes.
With its scarlet and black coloration, the iiwi is one of the more popular honeycreepers. It has a long bill shaped to fit the curved flowers of the lobelia tree — like a finger in a glove — and its complex song of whistles, squeaks and mechanical sounds is less melodic than the apapane's.
With its bright greenish-yellow plumage, the anianiau is a honeycreeper that acts like an American wood warbler, foraging among leaves and flowers. It has a short, thin, slightly curved bill, and its song is a series of rapidly repeated trills, often doubled-up: cheedle-ee, cheedle-ee.
Another common bird at Kokee is the Kauai amakihi, with its black mask and medium-length, sickle-shaped bill. A generalist, the amakihi feeds on nectar, fruits and insects gleaned from bark or leaves. Its trilling song — chi, chi, chi, chi — sometimes drops in pitch.
The akikiki was recently placed on the endangered species list; mosquito-borne avian malaria is its primary nemesis. The gray, brown and white bird forages like a nuthatch on the mainland. It has pink feet and a pink bill. It doesn't sing much, but its song is similar to the amakihi's.
The greenish-yellow akekee is located by its piercing single-note call, and its song — chi, chi, chi — shifts pitch. One of the rarer honeycreepers, the akekee has a bright yellow crown and rump and a black face mask. It uses its slightly crossed bill tips to open leaf buds on the ohia tree.