|Listed||March 11, 1967|
|Description||Green-backed male has a yellow head and underparts. The female is a uniform greenish-yellow.|
|Habitat||Mixed forests of 'ohi'a and koa.|
|Threats||Deforestation, dieback of 'ohi'a trees, predators.|
The akiapolaau, Hemignathus munroi, is a chunky-bodied honeycreeper that grows to about 6 in (15 cm) in length and 1oz (28.3 g) in weight. The green-backed male has a yellow head and underparts, while the female is a uniform greenish-yellow. The unique bill of the akiapolaau consists of a long sickle-shaped upper mandible and a short, straight lower one. This species was originally classified asH. wilsoni.
The akiapolaau moves along the main trunk and branches of forest trees gleaning beetle larvae and other insects from the bark. To get at its food, the akiapolaau holds its beak open and chisels at the bark with its stout lower mandible. It then picks out exposed insect larvae with the curved upper mandible. The breeding biology is largely unknown. Only two akiapolaau nests have ever been found, both abandoned before completion. Nests were discovered in October and February, but males have been heard singing virtually year round. These facts suggest that the species has a prolonged breeding period, but that individual birds nest infrequently. Akiapolaau have been observed in stable social groups of two adults and one young bird.
The akiapolaau inhabits mixed forests of 'ohi'a (Metrosideros collina ) and koa (Acacia koa ), although it shows a preference for the larger koa trees, where it forages on the trunk and bigger branches. Part of the population also inhabits mamane (Sophora chrysophylla ) and naio (Myoporum sandwicense ) forests. This species has not adapted to any varieties of non-native trees.
Endemic to the island of Hawaii, the akiapolaau was formerly found throughout the native forest from 1,300 ft (400 m) upward. The bird was reported in 1953 as being locally common on the eastern slopes of Mauna Loa at elevations of 4,000-7,300 ft (1,220-2,225 m) and on the northeastern slopes of Mauna Kea. Akiapolaau still retains its locally common status in the higher elevation koa and 'ohi'a forest on Mauna Loa, but it seems to be rarer in the mamane forests on Mauna Kea. It is very rare on the western slopes of Mauna Loa. It is found only rarely in Hawaii Volcanoes National Park and in the Keauhou-Kilauea area. Two widely separated populations also occur on the Kona coast. The population in the Ka'u Forest Reserve was estimated in 1988 to total about 1,500.
Most native forests on the island of Hawaii have been cleared and the land converted to agricultural or urban uses. Surviving upper-elevation forests have been much reduced by logging and conversion to pasture. In addition, forest acreage has been lost because of a widespread dieback of 'ohi'a. Dieback of these trees continues at elevations of 2,500-6,000 ft (760-1,830 m), primarily in the Hilo, Kau, Olaa, and Waikea areas. Reasons for the dieback are unknown, but it has been accompanied by a decline in native bird populations. Also, several bird predators have been introduced to Hawaii including the domestic cat, the Polynesian rat, the black or roof rat, the Norwegian rat, the mongoose, and the common mynah. These predators probably severely limit the akiapolaau's reproduction.
Conservation and Recovery
The U. S. Fish and Wildlife Service (FWS) recovery plan for the akiapolaau and similarly threatened forest birds explores ways to stem dieback of koa trees and to reclaim forest habitat. Primary goals are to restrict grazing animals, remove exotic predators and competitors, revegetate with native plants, and establish essential habitat areas as sanctuaries. In 1985 the FWS, together with the Nature Conservancy of Hawaii and the State of Hawaii, acquired 8,300 acres (3,360 hectares) of native forest on the island of Hawaii. This purchase is considered the first step in the establishment of the Hakalau Forest National Wildlife Refuge, designed primarily to preserve forest bird habitat. The refuge is situated on the northwestern slope of Mauna Kea and contains some of the most pristine koa-'ohi'a forests remaining on the islands. A 400-acre (162-hectare) parcel was acquired in 1988 by the Nature Conservancy and sold to the FWS for inclusion in the refuge.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U. S. Fish and Wildlife Service
Pacific Remote Islands Ecological Services Field Office
P. O. Box 50088
Honolulu, Hawaii 96850-5000
Telephone: (808) 541-1201
Fax: (808) 541-1216
U. S. Fish and Wildlife Service. 1982. "The Hawaii Forest Bird Recovery Plan." U. S. Fish and Wildlife Service, Portland, Oreg.