Data Zone
Justification of Red List category
This species has a very restricted range on one island where habitat degradation is ongoing. It is therefore assessed as Near Threatened.
Population justification
The population was estimated at 51,800 (46,500–57,100), based on a survey in 1991, with extrapolation of the observed densities to occupied habitat on the Ko`olau range and south Wai`anae region yielding estimated populations of about 49,500 ± 4,400 and 2,300 ± 900, respectively (Camp et al. 2009). This is placed in the band 40,000-60,000 individuals, roughly equivalent to 30,000-40,000 mature individuals. However, surveys on O`ahu, unlike those on other Hawaiian islands, have not been systematic, and these estimates may be too high (R. Shallenberger in litt. 1999). During surveys of the O‘ahu Forest National Wildlife Refuge in 2011, the species was not observed in sufficient numbers to estimate population densities and larger scale surveys are warranted (Camp et al. 2011).
Trend justification
Christmas Bird Counts indicate a population decline from 1958 to 1985 (Jacobi and Atkinson 1995, Lindsey et al. 1998), but further surveys have detected the species at lower elevations, indicating that the population may be stable and even increasing in some areas possibly as a result of resistance to avian malaria (Lindsey et al. 1998, 2020; Krend 2011). However, the current trend is not known.
The species was not observed in sufficient numbers during surveys in 2011 to estimate population densities (Camp et al. 2011). Increasing the numbers of stations sampled will be necessary to reduce uncertainty and yield greater power to detect trends in this species (Camp et al. 2011).
This species is endemic to O'ahu in the Hawaiian Islands (USA). It originally occurred throughout the island, but is now restricted to the two mountain ranges. In the Wai'anae Mountains, it is uncommon and sparsely distributed, mostly above 500 m elevation. In the southern and central Ko'olau Mountains, it is locally common, occurring from the summits occasionally down to 30 m in valleys, but it becomes increasingly rare northwards and is practically absent from the northern tip of the range (Lindsey et al. 1998).
It has adapted relatively well to forests of non-native trees, but is most abundant in native forests, particularly where koa trees dominate (Lindsey et al. 1998). It nests and forages in urban areas where enough trees grow (Lindsey et al. 1998). Little is known about its diet, but it probably feeds primarily on small insects and other arthropods, taking nectar and fruit as secondary food sources (Lindsey et al. 1998).
Feral ungulates and introduced predators are likely to have contributed to historical declines (Lindsey et al. 1998) and to be continuing limiting factors. There is thought to be continued loss of much of the remaining areas of lowland native habitats to development and invasive plants (Camp et al. 2009). Diseases spread by introduced mosquitoes were probably also a major factor, but some populations have developed some degree of resistance to avian malaria such that they can persist at lower elevations, and this may explain recent population increases in lowland areas (Lindsey et al. 1998, 2020; Krend 2011). Avian pox is potentially another threat to the species (Lindsey et al. 2020).
Conservation Actions Underway
No specific conservation measures are known for this species.
11 cm. Small honeycreeper with short, down-curved bill. Male all golden-yellow below, sharply contrasting with olive-green upperparts. Black lores, with yellow supraloral spot. Female greenish-grey above, pale yellowish-white below, with prominent wing-bars of same colour. Dark grey lores, yellowish-white supraloral spot. Juvenile male duller than adult, with two buffy wing-bars. Similar spp. Male O`ahu `Alauahio Paroreomyza maculata has straight bill, bold yellow stripe over eye and dark stripe through eye. Female has dark line behind eye only and pale lores. Introduced Mountain White-eye Zosterops japonicus has straight bill, bold white eye-ring. Voice Song a vigorous trill of single notes. Call a short cat-like buzzy note. Hints Easily seen at fairly low elevation around flowering trees in mountains behind Honolulu.
Text account compilers
Vine, J.
Contributors
Camp, R. & Shallenberger, R.
Recommended citation
BirdLife International (2024) Species factsheet: Oahu Amakihi Chlorodrepanis flava. Downloaded from
https://datazone.birdlife.org/species/factsheet/oahu-amakihi-chlorodrepanis-flava on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.