ʻAkiapolaʻau

The ʻakiapōlāʻau occurs mainly in old-growth mesic and wet forests in Kaʻū, Hilo District, and Hamakua. Koa (Acacia koa) and ʻōhiʻa lehua (Metrosideros polymorpha) are dominant canopy species in its habitat. Disease-carrying mosquitoes have restricted it to elevations of between 1,300 and 2,100 metres (4,300 and 6,900 ft). It formerly inhabited māmane (Sophora chrysophylla) and naio (Myoporum sandwicense) dry forests at elevations of 1,900 to 2,900 metres (6,200 to 9,500 ft) on Mauna Kea, but this population was extirpated in 2002.

It feeds on insects which are found hidden within the branches of the trees, along with the nectar of flowers shaped like its bill. It also looks for invertebrates at the floor of the forest where there is a large amount of natural growth. This bird uses its long bill to peck open the bark to reach the larvae; it then uses its thin upper bill to probe out the meal and its lower bill to crush its meal.

The English common name was adopted around 1905, directly from the Hawaiian-language name ʻakiapōlāʻau. The genus name, Hemignathus, is of Greek origin, meaning 'half-jawed', a reference to the shorter mandible compared to the maxilla in birds of this genus. The specific epithet, wilsoni, honours the British ornithologist, Scott B. Wilson, renowned for his monumental work, Aves Hawaiiensis: The Birds of the Sandwich Islands (1890–1899). This species is monotypic.