WatchList Species Account for ‘Akiapola’au |
Qualifies for the list as a Red List Species
|Photo: Jack Jeffrey
Endemic to the island of Hawaii, the ‘Akiapola’au was described by early naturalists as common to abundant throughout its range, but clearing of lower elevation forests during the 1900s split the population into four subunits in remnant native forest above 4,900 feet. Only one of these four subpopulations survives in significant numbers, with the other three subpopulations reduced to an estimated 44 birds, 20 birds, and 3 birds respectively. In 1990-95 the total numbers of the bird were estimated at 1,163 individuals. Among the protected sites with significant populations are Hakalau Forest National Wildlife Refuge and Ka’u Forest Reserve.
The ‘Akiapola’au occupies a woodpecker-type niche, creeping along trunks and branches and probing for grubs and various arthropods within the bark. Its tools for doing so are entirely different from that of a woodpecker; this honeycreeper has a long, downward-curving upper mandible that it uses to probe, and a short, awl-like lower mandible it uses to tap. It forages mainly on the koa tree, selecting lichen-covered and dead branches to search for arthropods. The bird also drinks sap from shallow wells it drills in live bark of ‘ohi’a-lehua trees.
Generally the Akiapola’au raises only one young a year, which remains with its parents for many months. Because it has such a slow reproductive rate, it is slow to recover when its populations are reduced.
Threats include grazing and logging that have degraded or destroyed much of its habitat; predation by introduced mammals, including feral cats, which are ubiquitous in the bird’s habitat; rat, and native raptors; mosquito-borne avian diseases; and depletion of the bird’s prey by introduced predatory and parasitic insects. Global climate change could facilitate mosquitoes moving to higher elevations, thus decreasing the habitat for this and other native Hawaiian passerines even further.
Habitat restoration work is underway for the ‘Akiapola’au; sheep and mouflon have been removed from Mauna Kea, allowing regeneration of the mamane forest, while removal of cattle and fencing have been used at other reserves. Conservation measures that should also be taken include protection of remaining old-growth native forest above the zone where mosquitoes are present, removal of all feral ungulates, and captive propagation. Reforestation of degraded sites that could support Akiapola'au should also be initiated.