Akiapolaau Life History

Habitat

Akiapolaau inhabit native Hawaiian forests that contain both koa and ohia lehua trees. These forests include mostly undisturbed closed-canopy forests, open forests that were grazed but still have an intact canopy, and reforested pastures replanted with koa. Akiapolaau forage primarily in koa trees and nest almost exclusively in ohia lehua. Once considered common and widespread on the island of Hawaii, this species is now restricted to higher-elevation forests on the island above roughly 1,500 meters (5,000 feet).

Food

Akiapolaau feed primarily on caterpillars, beetles (both adults and larvae), and spiders. They hitch their way along branches and twigs and use their unique bill to test bark and epiphytes. Once they detect hidden insects or spiders, Akiapolaau hammer with their short lower mandible to expose the prey and then use the long, curved upper mandible to extract it. This species also feeds on ohia lehua sap year-round, drilling many shallow holes into live bark as sapsuckers do in North America.

Nesting

Nest Placement

Typically placed at the ends of leafy branches high in ohia lehua trees, with nest heights ranging from 7–22 meters (23–72 feet).

Nest Description

An open cup built of twigs, stems, and rhizomes and surrounded by a “picket fence” of bark strips sticking up from the rim.

Nesting Facts

Behavior

Akiapolaau are nimble foragers, hopping along larger branches, clinging to vertical branches, hanging upside down, and occasionally using its hooked bill as a third limb, like a parrot. They typically move around as lone males, pairs, or small family groups with two parents and their latest offspring. Akiapolaau frequently join mixed-species feeding flocks that may include Hawaii Akepa, Hawaii Creeper, Hawaii Amakihi, or Palila.

Conservation

The International Union for Conservation of Nature lists Akiapolaau's conservation status as Endangered. The entire Akiapolaau population was estimated at 1,900 individuals in 2015. The main threats to this species are introduced avian diseases (pox and malaria) and habitat destruction caused by invasive species, especially pigs and sheep.

Credits

Pratt, H.D., Bruner, P.L. and Berrett, D.G. (1987). A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton Univ. Press, Princeton, New Jersey.

Pratt, T. K., S. G. Fancy, C. J. Ralph, S. G. Mlodinow, and P. Pyle (2024). Akiapolaau (Hemignathus wilsoni), version 2.0. In Birds of the World (N. D. Sly, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.akiapo.02

Raine, H. and A. F. Raine (2020). American Birding Association Field Guide to Birds of Hawai'i. Scott & Nix, Inc. New York, NY, USA.

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