|Scientific Name:||Loxops caeruleirostris|
|Species Authority:||(Wilson, 1890)|
|Identification information:||11 cm. Small, finch-like bird with notched tail and conical bill with slightly crossed tips (hard to see in the field). Male basically olive-green above, yellow below, with black mask surrounding bill to behind eye. Yellow forehead, forecrown and rump. Pale blue bill sometimes with dark tip. Female similar except colours muted and black mask less extensive. Similar spp. All other "little green birds" on Kaua`i (Kaua`i `Amakihi Hemignathus kauaiensis, `Anianiau H. parvus and introduced Japanese White-eye Zosterops japonicus) have dark rumps. Kaua`i Nukupu`u H. lucidus hanapepe has yellowish rump, but is much larger with longer black bill. Voice Songs are lively trills that shift pitch and speed. Call a piercing, upslurred szeet. Hints Feeds almost exclusively in terminal leaf clusters of ohi`a trees (not in flowers). Can be seen on trails east of Koke`e.|
|Red List Category & Criteria:||Critically Endangered A3ce+4ace ver 3.1|
|Contributor(s):||Camp, R., Fretz, S., Gorresen, M., Roberts, P., VanderWerf, E., Woodworth, B., Morrey, S., Laut, M., Behnke, L., Crampton, L., Paxton, E., Vetter, J. & Pejchar, L.|
|Facilitator/Compiler(s):||Benstead, P., Capper, D., Derhé, M., Isherwood, I., Mahood, S., Stattersfield, A., Stuart, T., Symes, A., Taylor, J., Wright, L & Ashpole, J|
This species is classified as Critically Endangered owing to an extremely rapid decline in population size over the last ten years. Urgent action is required to halt the decline of this species, which until relatively recently was considered not uncommon.
|Previously published Red List assessments:||
|Range Description:||The species is endemic to Kaua`i in the Hawaiian Islands (U.S.A.). It was common throughout upper elevation forests in the late 19th century and was thought to be stable at c.20,650 individuals up until the mid 1990s, although its habitat declined in extent over this time period (USFWS 1983, Scott et al. 1986, Lepson and Pratt 1997, S. Fretz et al. in litt. 2003). However, in 2000, surveys indicated that the population was 7,839 ±704 individuals, which has since decreased to 5,669 ± 1,003 individuals in 2005, 3,536 ± 1,030 in 2007 and 945 individuals (460-1,547, 95% CI) in 2012 (L. Crampton et al. in litt. 2015). Even allowing for the large error estimates this indicates a dramatic decline (Holmer 2007, D. Kuhn per Holmer 2007, D. Pratt per Holmer 2007, VanderWerf 2007). It occurs at the highest density in the remote Alaka`i region, and also occurs in the upper Waimea and Koke`e regions, and an isolated population persisted in the Makaleha Mountains until at least the early 1970s (Scott et al. 1986, Lepson and Pratt 1997).
Native:United States (Hawaiian Is.)
|Continuing decline in area of occupancy (AOO):||Yes|
|Extreme fluctuations in area of occupancy (AOO):||No|
|Estimated extent of occurrence (EOO) - km2:||5|
|Continuing decline in extent of occurrence (EOO):||Yes|
|Extreme fluctuations in extent of occurrence (EOO):||No|
|Number of Locations:||2|
|Continuing decline in number of locations:||Unknown|
|Extreme fluctuations in the number of locations:||No|
|Lower elevation limit (metres):||600|
|Upper elevation limit (metres):||1600|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The most recent population estimate is from 2012 when the number of individuals was estimated at 945 (460-1,547, 95% CI) (L. Crampton et al. in litt. 2015). This equates to approximately 310-1,000 mature individuals.
Trend Justification: It was common throughout upper elevation forests in the late 19th century and was thought to be stable at c.20,650 individuals up until the mid-1990s, although its habitat declined in extent over this time period. However, in 2000, surveys estimated that the population was 7,839 ± 704 individuals, which has since decreased to 5,669 ± 1,003 individuals in 2005, 3,536 ± 1,030 in 2007 (VanderWerf 2007) and 945 individuals (460-1,547, 95% CI) in 2012 (L. Crampton et al. in litt. 2015). Thus the population is estimated to have declined very rapidly over the last ten years, and is expected to decline extremely rapidly over the next ten years.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||It inhabits wet `ohi`a, `ohi`a/olapa and diverse mesic forest, appearing to tolerate considerable habitat disturbance if sufficient `ohi`a remains. It is found at 600-1,600 m, mostly above 1,100 m, and apparently never occurred in lowland forests. It feeds primarily on spiders and insects, taking nectar very rarely. Breeding occurs at least in March and April, possibly February to June, and all known nests have been in `ohi`a trees (Lepson and Pratt 1997).|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||5.8|
|Movement patterns:||Not a Migrant|
|Major Threat(s):||Development is reducing habitat availability in the Koke`e region, while the spread of exotic plants and feral ungulates is degrading remaining areas (Loope and Medeiros 1995, Lepson and Pratt 1997). Avian pox and malaria probably cause mortality because introduced mosquitoes (vectors for these diseases) are now common at 900 m, may breed at 1,200 m, and appear to be encroaching on the Alaka`i plateau (Herrmann and Snetsinger 1997, Lepson 1997, Lepson and Pratt 1997). There is concern that rising average temperatures could allow mosquitoes to survive at higher elevations and increase the exposure of birds to disease (Holmer 2007). A small increase in temperature is predicted to eliminate much of the mosquito-free zone on Kaua`i (U.S. Geological Survey per Holmer 2007) and a recent study has found evidence of this. 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). Food resources may be limited by alien wasps and ants which greatly reduce populations of native arthropods (Lepson and Pratt 1997). Introduced birds may also be competitors and introduced predators (particularly rats) probably cause some mortality (Lepson and Pratt 1997). Adverse weather may be a significant limiting factor, e.g. prolonged, heavy rains which can result in nesting failure and cause massive mortality among fledglings and juveniles (Lepson and Pratt 1997). Two recent hurricanes resulted in serious damage to Kaua`i's forests (Pratt 1994).|
Conservation and Research Actions Underway
Much of the current range is protected by Alaka`i Wilderness Preserve and, to some extent, by Koke`e State Park. In 2010 it was added to the endangered species list (Foote 2010). In April 2007, the Hawaii Department of Land and Natural Resources began to conduct population surveys of forest birds on Kaua`i to verify anecdotal evidence of a recent crash in the species's numbers (Holmer 2007). A captive breeding programme 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). Rodent control has also been initiated with preliminary results suggesting rat numbers have declined (L. Crampton et al. in litt. 2015).
Conservation and Research Actions Proposed
Key priority actions to conserve the species were recently identified: develop a captive breeding population, control rodents, provide supplementary food, locate and control sources of mosquito populations and habitat management (L. Crampton et al. in litt. 2015). Continue to conduct population surveys, especially in peripheral parts of its range. Research basic ecology. Prevent further habitat degradation and restore habitat. Control and prevent further introductions of alien species; fence out and remove invasive species (Holmer 2007). Identify and translocate disease-resistant birds to parts of the historical range that are affected by disease-carrying mosquitoes (Lepson and Pratt 1997).
|Citation:||BirdLife International. 2015. Loxops caeruleirostris. The IUCN Red List of Threatened Species 2015: e.T22720832A77733637. . Downloaded on 27 May 2016.|
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