|Scientific Name:||Hemignathus flavus|
|Species Authority:||(Bloxham, 1827)|
|Red List Category & Criteria:||Vulnerable D2 ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
|Contributor/s:||Camp, R., Fretz, S., Gorresen, M., Shallenberger, R., VanderWerf, E. & Woodworth, B.|
This species is classified as Vulnerable because it has a very small range. It is restricted to two mountain ranges on one island, and, although it has apparently adapted to non-native habitats, it remains at risk from the effects of exotic taxa, especially the possible introduction of disease-carrying mosquitoes capable of tolerating the cooler climate at high altitudes.
|Range Description:||Hemignathus flavus 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). The population is estimated at 20,000-60,000 birds (Jacobi and Atkinson 1995, Lindsey et al. 1998), but 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). Christmas bird counts indicate a population decline over the period 1958-1985 (Lindsey et al. 1998), but more recent information indicates that the population may be stable and even increasing in some areas (Jacobi and Atkinson 1995, Lindsey et al. 1998).|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population is estimated at 20,000-60,000 birds, roughly equivalent to 13,000-40,000 mature individuals, but 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).|
|Habitat and Ecology:||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).|
|Major Threat(s):||Feral ungulates and introduced predators are likely to have contributed to historical declines (Lindsey et al. 1998) and to be continuing limiting factors. Diseases spread by introduced mosquitoes were probably also a major factor, but some populations have apparently developed some degree of resistance to avian malaria, and this may explain recent population increases in lowland areas (Lindsey et al. 1998).|
Conservation Actions Underway
No specific conservation measures are known for this species. Conservation Actions Proposed
Monitor the population. Perform further research (Lindsey et al. 1998), especially on the reasons for its relative scarcity in the Wai`anae Mountains. Protect native habitats by law. Reforest cleared areas.
|Citation:||BirdLife International 2012. Hemignathus flavus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.|
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