Habitat
Old-growth mesic and wet koa Acacia koa and `ohi`a Metrosideros polymorpha forest between 1,300 and 2,100 m in Ka`u, Hamakua and perhaps still in Kona. It formerly occupied dry mamane and naio woodlands from 1,900 to 2,900 m on Mauna Kea.
Population
Estimated population is 1,200 (2010) and decreasing.
Status EN
Habitat destruction and degradation through grazing and logging (particularly of koa), predation by introduced rats, feral cats and native raptors, and avian diseases spread by introduced mosquitoes, are the main threats.
For more information see BirdLife International Species Factsheet.
Voice
Song is a short, rapid warble. Calls include an upslurred whistle, a very short warble 'cheedle-ee', and a short 'sweet'. Juveniles utter a loud 'chewp' as sound beacon to attendant adults.
Akiapolaau (Hemignathus wilsoni) [XC144826]
by George Wagner from Hakalau Forest NWR, Hawaii, Hawaii, United States (song)
Akiapolaau (Hemignathus wilsoni) [XC58926]
by Brooks Rownd from Hakalau NWR, E slope Mauna Kea, Hawai'i (Big Island), HA, United States (call, a male, tapping at ends)
Subspecies
Genus sometimes listed as Heterorhynchus, but this name is an objective synonym of current genus name. It is unclear which name published earlier, and current genus name was adopted using Principle of First Reviser.
No subspecies.
Similar Species
Hawaii Amakihi (Chlorodrepanis virens) which is similarly coloured but much smaller with proportionally smaller bill.
References
See References.
BirdLife International Species Factsheet