WatchList Species Account for Oahu ‘Alauahio |
Qualifies for the list as a Red List Species
© H. Douglas Pratt, Birds of Hawaii. Reprinted by permission of Princeton University Press.
The Oahu 'Alauahio, also known as the Oahu Creeper, was endemic to the island of Oahu; the species was common there in the late 19th century, but rare by 1930. The last probable sighting was in 1990. The final sightings of this species were in the mid to upper regions of the Ko’olau Mountains between 980 and 2,132 feet, where there is remnant native lowland forest that has been degraded by introduced plants. Extensive surveys by state biologists in 1992 failed to detect the species, which is now considered extinct, although it is still listed as federally endangered.
The species is very similar to the Oahu Amakihi, and many of the recent claims of sightings may be due to confusion with the latter species.
The Oahu 'Alauahio's natural history is little-known, but the presumption is that it resembled its congener, the Maui 'Alahahio. The bird apparently fed on invertebrates and was never observed feeding on nectar. It foraged on trunks and limbs of trees and shrubs, probing the bark for insects.
Deforestation and mosquito-borne avian diseases are likely among the chief reasons for this bird's disappearance. Predation may also have played a role, though there is no evidence to support this theory, since the bird had become so rare even 70 years ago. Presumably Short-eared Owls and introduced cats, rats and mongoose preyed on the birds, and pigs and other domestic ungulates degraded its habitat.
Although pigs were introduced to the Hawaiian Islands by the Polynesians, they were usually kept in the villages as a valuable resource. European pigs were introduced by sailors in the late 1700s, and through tearing open tree fern trunks for food and creating wallows, they degraded the habitat and created breeding sites for mosquitoes. Goats and cattle also considerably reduced native forests before the advent of the 20th century.