|Scientific Name:||Loxops caeruleirostris|
|Species Authority:||(Wilson, 1890)|
|Red List Category & Criteria:||Critically Endangered A3ce+4ace ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Contributor(s):||Camp, R., Fretz, S., Gorresen, M., Roberts, P., VanderWerf, E. & Woodworth, B.|
|Facilitator/Compiler(s):||Benstead, P., Capper, D., Derhé, M., Isherwood, I., Mahood, S., Stattersfield, A., Stuart, T., Symes, A. & Taylor, 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.
Loxops caeruleirostris is endemic to Kaua`i in the Hawaiian Islands (USA). 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 and to 3,536 ± 1,030 in 2007. 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).
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Survey results predict the population to number 2,500-4,566 individuals, roughly equivalent to 1,700-3,000 mature individuals.|
|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).|
|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). 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 Actions Underway
Much of the current range is protected by Alaka`i Wilderness Preserve and, to some extent, by Koke`e State Park. 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). Conservation Actions Proposed
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). Initiate a captive breeding programme (Holmer 2007). List under the Endangered Species Act as a matter of emergency (Holmer 2007).
|Citation:||BirdLife International 2012. Loxops caeruleirostris. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 19 September 2014.|
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