Data Zone
Justification of Red List category
This species qualifies as Critically Endangered because it has an extremely small and declining population, confined to one upland area where it is at risk from the effects of hurricanes and exotic taxa, including predators and disease.
Population justification
The most recent population estimate from 2012 is 468 individuals (231-916, 95% CI) (L. Crampton et al. in litt. 2015). This equates to approximately 150-610 mature individuals.
Trend justification
The population has declined dramatically since the 1960s and this trend appears to be continuing owing to a number of threatening processes. During 1968-1973, the total population was estimated at 6,832 (±966 standard error) (USFWS 1983). The most recent estimates from 2012 suggest the population has decreased to 468 individuals (231-916, 95% CI) (L. Crampton et al. in litt. 2015). This represents a reduction of 67% across three generation lengths (assuming exponential decline), here placed in the band 50-79%.
This species was common and widely distributed in the 1890s on Kaua`i in the Hawaiian Islands (U.S.A.). During 1968-1973, the total population was estimated at 6,832 (±966 standard error), when it was recorded on the Laau ridge and was fairly widespread in Koke'e (USFWS 1983). Since then, the population has declined and the species has retreated from the Koke`e region and the fringes of the Alaka`i region, and is now uncommon to rare in the Alaka`i (Pratt et al. 1987, Pratt 1993, 1994, Behnke et al. 2016). Recent unpublished survey data indicate dramatic declines (85-89% since 1968-1973) and a decline of c. 64% in its core area in the Alaka`i Swamp from 1970 to 2000 (Anon 2007). The population was estimated to number 1,312 ± 530 birds, based on surveys conducted in April and May 2007 (Hawaii Division of Forestry and Wildlife and USGS, unpublished.data), occupying an area of just 36 km2 (Foster et al. 2004). The most recent estimates from 2012 suggest the population has decreased further to 468 individuals (231-916, 95% CI) (L. Crampton et al. in litt. 2015).
It is found in high-elevation `ohi`a and koa-`ohi`a forest, but the latter is mainly distributed in the Koke`e region, from where it is retreating (USFWS 1983, Scott et al. 1986, Pratt 1993). The Alaka`i stronghold is at 1,000-1,600 m. However, the 1968-1973 surveys found the species at lower altitudes in a few areas, and it may not occur above 1,500 m (USFWS 1983, Scott et al. 1986). The species prefers intact forests with a high canopy (Behnke et al. 2016). It feeds on invertebrates (Scott et al. 1986, Pratt et al. 1987), and has been observed excavating rotting wood from the centre of a twig, presumably for insect larvae (VanderWerf and Roberts 2008). Both parents have been observed bringing food to the nest, with the male providing some food for the female, though the female does also forage independently. A nesting pair in 2007 had a juvenile from a previous nest, indicating the species will attempt to raise two broods (VanderWerf and Roberts 2008).
Lowland forests have been cleared for timber and agriculture, with feral livestock causing further degradation and destruction (USFWS 1983, Scott et al. 1986). Feral pigs continue to be particularly detrimental, additionally dispersing alien plants and facilitating the spread of introduced mosquitoes which transmit avian malaria and avian pox (Scott et al 1986, Pratt 1994, Loope and Medeiros 1995). Domestic and introduced birds provide reservoirs for these diseases, to which there is little resistance in Hawaiian honeycreeper populations (USFWS 1983, Scott et al 1986, Pratt 1994, Lepson 1997). Predation by introduced animals and competition for arthropod resources by introduced taxa (especially Japanese White-eye Zosterops japonicus, wasps and ants) are additional threats (USFWS 1983, Scott et al 1986, Jacobi and Atkinson 1995, Lepson 1997). Introduced plants such as Kahili Ginger (Hedychium gardnerianum), Blackberry (Rubus argutus), Strawberry Guava (Psidium cattleianum), Australian Tree Fern (Cyathea cooperi) and Firetree (Myrica faya) have degraded much native forest in Koke'e, and threaten the remaining habitat.
Hurricanes have had major impacts on population size in the past; in 1992 Hurricane Iniki devastated forests throughout Kaua`i, and all bird populations on the island appeared to have been drastically reduced (Pratt 1993, 1994), although some have since recovered. Hurricanes are now thought to displace birds from the small area of suitable habitat at higher elevations and push them into the lowlands where avian malaria is prevalent (Anon. 2007). A growing concern is that rising temperatures could allow mosquitoes to survive at higher altitudes and further transmit avian malaria and avian pox (Anon. 2007) as evidenced by a recent study; over the past two decades there has been a significant increase in the prevalence of avian malaria across the altitudinal range of the Alaka’i Plateau, which coincides with increasing air temperatures and changing patterns of precipitation and streamflow which support increased transmission of the disease (Atkinson et al. 2014) and having a montane distribution that is close to the maximum altitude within its range, this species is potentially susceptible to climate change (BirdLife International unpublished data).
Conservation and Research Actions Underway
It was added to the Endangered Species list in 2010 (Foote 2010). It occurs within the Alaka`i Wilderness Preserve, but has declined dramatically within this area. Starting in April 2007, the Hawaii Department of Land and Natural Resources conducted population surveys of forest birds on Kaua'i to determine trends. The Zoological Society of San Diego is developing techniques for rearing Oreomystis creepers from eggs and breeding them in captivity, using the related Hawai`i Creeper, at the Keauhou Bird Conservation Center (USFWS 2003). The Hawai`i Creeper has been successfully propagated in captivity, and release of the captive population is planned (USFWS 2003, P. Roberts in litt. 2007). A captive breeding programme for Akikiki was started in 2015, as a collaboration between Kauai Forest Bird Recovery Project, State Department of Land and Natural Resources' Division of Forestry and Wildlife, U.S. Fish and Wildlife Service - Pacific Islands Fish and Wildlife Office and San Diego Zoo Global (Buley 2015, L. Crampton et al. in litt. 2015). Eggs are harvested from wild nests and the chicks hatched at San Diego Zoo Global's facilities in Hawaii (Buley 2015). The Kaua'i Watershed Alliance and The Nature Conservancy are considering fencing the north-eastern section of the Alakai Plateau on Kaua'i where the species was last recorded to exclude herbivores and possibly other predators. Rodent control has been initiated, with preliminary results suggesting rat numbers have declined (L. Crampton et al. in litt. 2015).
13 cm. Quiet bark-picker with conical, slightly downcurved bill. Adult grey-brown above, white below with pink bill and feet. Juvenile has bold white eye-ring. Similar spp. Female Kaua'i Nukupu'u Hemignathus lucidus hanapepe greener above with yellow tinges around face. `Elepaio Chasiempis sandwichensis has white rump, tail tip, and wing spots. Voice Song a short, descending trill. Call a simple weet. Juveniles following adults utter stuttering series of short notes chit-chit, chi-chi-chit, chit. Hints Forages slowly along trunks and branches, occasionally among flowers. Found in low numbers along Alaka`i Swamp Trail near Koke`e.
Text account compilers
Symes, A., Wright, L, Benstead, P., Derhé, M., Harding, M., Hermes, C., Bird, J., Ashpole, J, Isherwood, I., Stuart, T.
Contributors
Gorresen, M., Roberts, P., Crampton, L., Woodworth, B., Camp, R., Paxton, E., Fretz, S., VanderWerf, E., Behnke, L., Vetter, J., Laut, M., Pejchar, L., Morrey, S.
Recommended citation
BirdLife International (2024) Species factsheet: Akikiki Oreomystis bairdi. Downloaded from
https://datazone.birdlife.org/species/factsheet/akikiki-oreomystis-bairdi on 22/11/2024.
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 22/11/2024.