Hawaii Creeper

Oreomystis mana

Description

The Hawaii creeper, Oreomystis mana, is a sparrow-sized bird that grows to about 5 in (12.7 cm) in length and 0.5 oz (15.5 g) in weight. It has a thick, pale, and slightly curved bill. Plumage is predominantly olive-green on the back and yellow-brown below. The throat is white. Field identification is complicated by the creeper's similarity to the Amakihi, Hawaii Akepa, and Japanese White-eye. This species was previously classified as Loxops mana.

Behavior

The Hawaii creeper is usually solitary, although it is sometimes found in small family groups. It gleans insects from tree bark. Little is known of its breeding biology and natural history. It breeds from January to as late as August. The clutch size is probably two eggs, which are laid in a nest built in the crotch of a limb or between the bark and trunk of the Koa tree. One pair was observed to build a nest in 14 days. Incubation has been observed to last 13 days, with fledging occurring after 20 days. The females are the primary caregiver. Active nests have been found in January and February. This creeper generally feeds on insects gleaned from the trunks and branches of mature trees; beetle larvae make up a large part of its diet.

Habitat

The Hawaii creeper inhabits mesic to wet ohia, koa-ohia, and koa'mamane forests at elevations between 2,700 and 8,580 ft (822.9 and 2,615.2 m). The highest densities occur in mesic forests dominated by koa between 5,800 and 7,400 ft (1,767.8 and 2,255.5 m) in elevation. The creeper has also inhabited open pastures on Mauna Kea's northeast slope. Nine nests have been reported—six in koa trees and three in ohias. Two of these nests were in cavities, and seven were open cupped nests. Nest heights were from 39 to 74 ft (11.9 to 22.6 m) above ground. Mosses and liverworts covered the outside of the nest; liverworts and ferns made up the body; and branch fibers lined the cup.

Distribution

The Hawaii creeper was formerly found in the ohia and mixed ohia-koa forests throughout the island of Hawaii. It was common in the Kona and Kau districts, as well as in the forests above Hilo. Sitings made in 1972 have not been confirmed and were probably misidentifications. Presently found throughout upper-elevation native forests on the eastern coast, the Hawaii creeper is locally rare to common on Keauhou Ranch and on the eastern slopes of Mauna Loa. It is rare on the western coast. A few birds have been seen in the Hawaii Volcanoes National Park. Citings may occur at lower and higher elevations in the same areas, including Pohakuloa Flats, an U. S. Army training area. The most recent population estimate for the Hawaii creeper was 24,780 birds in 1986.

Threats

Like many of Hawaii's forest birds, the Hawaii creeper declined due to deforestation of the islands. Hawaii's forests have been drastically reduced by logging and the subsequent conversion of land to crops and pasture. Today, most forest areas below 2,600 ft (800 m) have been converted to agricultural or urban uses. Wetter forest on the island are subject to rooting by feral pigs, which uproot native plants and spread the seeds of competing exotic plants, such as banana poka and strawberry guava. Widespread dieback of ohia, Hawaii's most common native forest tree, has recently modified large tracts of forest on the island of Hawaii, and additional areas may be threatened. Research is under way to determine whether this dieback is a recurrent natural phenomenon. Dieback continues between the elevations of 2,500-6,000 ft (760-1,830 m), primarily in the Hilo, Kau, Olaa, and Waikea areas. In addition to habitat loss, the Hawaii creeper and other forest birds are vulnerable to avian pox and malaria that are spread by mosquitoes. Mosquitoes were first introduced to the islands in the 1820s. Loss of native birds is especially evident at lower elevations, where mosquitoes are most numerous. Other introduced insects, such as parasitic wasps and predaceous ants, have eliminated many native insects, which served as food for the creeper.

Conservation and Recovery

Recovery of the Hawaii creeper and other forest birds depends on the preservation and restoration of a large, contiguous tract of native forest habitat. In 1985, the U. S. Fish and Wildlife Service, together with the Nature Conservancy of Hawaii and the State Department of Land and Natural Resources, purchased 8,300 acres (3,360 hectares) of native forest as the first phase in a proposed 33,500-acre (13,560-hectare) Hakalau Forest National Wildlife Refuge. Designed primarily to preserve the habitat of endangered forest birds, the refuge is located on the northwestern slope of Mauna Kea. In 1988 another 400 acres (162 hectares) was added to the refuge.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
(503) 231-6121
http://pacific.fws.gov/

U. S. Fish and Wildlife Service
Field Office of Endangered Species
300 Ala Moana Blvd., Room 6307
P.O. Box 50167
Honolulu, Hawaii 96850

References

Scott, J. M., S. L. Conant, and H. D. Pratt. 1979."Field Identification of the Hawaiian Creeper on the Island of Hawaii." Western Birds 10: 71-80.

U. S. Fish and Wildlife Service. 1982. "The Hawaii Forest Bird Recovery Plan." U. S. Fish and Wildlife Service, Portland.