Akiapolaau Hemignathus wilsoni Scientific name definitions
- EN Endangered
- Names (20)
- Monotypic
Revision Notes
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Species names in all available languages
Language | Common name |
---|---|
Catalan | akiapolaau |
Croatian | tankokljuna havajka |
Dutch | Akiapolaau |
English | Akiapolaau |
English (HAW) | ʻĀkiapōlāʻau - Akiapolaau |
English (United States) | Akiapolaau |
French | Akiapolaau d'Hawaï |
French (Canada) | Akiapolaau d'Hawaï |
German | Hawaii-Sichelkleidervogel |
Japanese | カワリハシハワイミツスイ |
Norwegian | akiapolaau |
Polish | hawajka pełzaczowata |
Russian | Акиполау |
Serbian | Akiapolaau |
Slovak | havajčan hákozobý |
Spanish | Akiapolaau |
Spanish (Spain) | Akiapolaau |
Swedish | akiapolaau |
Turkish | Akiapöleo |
Ukrainian | Акіаполау |
Revision Notes
Steven G. Mlodinow revised the account. Peter Pyle contributed to the Plumages, Molts, and Structure page. Steven G. Mlodinow and Arnau Bonan Barfull curated the media.
Hemignathus wilsoni (Rothschild, 1893)
Definitions
- HEMIGNATHUS
- wilsoni
The Key to Scientific Names
Legend Overview
Introduction
Hawaiian honeycreepers, famous as an example of adaptive radiation on islands, include species that converge in their appearance and way of life on more familiar birds from continents. While some honeycreepers retain an ancestral finchlike form and life history, others resemble and behave like sunbirds, warblers, or nuthatches. In contrast to this convergence, evolution has drawn a few honeycreepers out on novel pathways. What more bizarre evolutionary tangents could one imagine than the Akiapolaau? In the absence of woodpeckers, these birds capture invertebrates living in bark or wood, but their tools and methods are entirely different. No other birds have, in a sense, evolved two bills in one. The long upper mandible curves downward like a black wiry hook, whereas the short, robust lower mandible juts straight forward as a sharp-pointed awl.
Equipped with such tools, the tree-dwelling Akiapolaau sets out foraging. Hitching its way along branches and twigs, the bird tests bark and epiphytes, pausing inquisitively to tap with the awl or probe with the hook. Once it detects a hiding caterpillar or spider, the bird goes to work excitedly. Noisily pounding and yanking, the Akiapolaau excavates the substrate in pursuit of its retreating quarry. Ultimately the prey is cornered, hooked out into the open, and flogged against the bird's perch before being gulped down.
Perhaps its peculiar bill is unsuited to taking nectar, but whatever the reason, the Akiapolaau usually ignores flowers. It does drink sap from the small, shallow wells it drills in live bark. A bird selects a few individual trees for drilling and visits each repeatedly, so that eventually a large surface of the tree's bark becomes peppered with holes. Drinking sap does not come easily for an Akiapolaau, however, and requires the bird to tilt its head upward so that the fluid runs down inside the mandible guided by a short, fringed tongue. This behavior resembles sap-sucking by woodpeckers. The bill of a young Akiapolaau seems to take many months to grow and harden, and during this time the juvenile remains with its parents. Protected on the family's large territory, the young bird slowly learns foraging skills. Generally only one young fledges, the sole offspring raised by its parents that year.
The Akiapolaau survives as an endangered species on its home island of Hawai'i. Restricted to remnant forest above 1,500 m elevation, the total population numbers about 1,900 birds. Because the species prefers foraging on koa (Acacia koa), but nests almost exclusively in the crowns of 'öhi'a lehua (Metrosideros polymorpha), the best habitat includes both tree species. Factors limiting its population and distribution include mosquito-borne diseases and the loss and fragmentation of habitat. Depredation by feral cats (Felis catus) and rats (Rattus spp.) and depletion of its arthropod prey base by imported predatory and parasitic insects are likely threats. Concern for the Akiapolaau has resulted in habitat protection and restoration in key parts of its range. With expanded management, the Akiapolaau can be spared the fate of its less fortunate congeners, the extinct species of nukupuus.
"Of all the native Drepanid birds none are more interesting in their habits than the species of Heterorhynchus" (1). These admiring words, written a hundred years ago by the person most familiar with Akiapolaau and its congenerics, the nukupuus (then known under genus Heterorhynchus), still ring true today. Yet despite the charm and novelty of these birds, we know surprisingly little about them. Naturalists from the 1800s described their distributions and habits at a time when both species were much more numerous. Recent information on Akiapolaau is taken from the modest body of existing published research and gleaned from data contributed by numerous field biologists. It includes a three-year, weekend study of a now-extirpated color-banded population at Kanakaleonui on Mauna Kea (1989–1992; T. K. Pratt and P. Chang). This fascinating species has yet to be the focus of intensive field research.
- Year-round
- Migration
- Breeding
- Non-Breeding