Species

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Justification
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.

Taxonomic source(s)
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Identification
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.

Distribution and population
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).


Population justification
Survey results predict the population to number 2,500-4,566 individuals, roughly equivalent to 1,700-3,000 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 and to 3,536 ± 1,030 in 2007 (VanderWerf 2007). 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.

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).

Threats
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).

References
U. S. Fish and Wildlife Service. 1983. Kauai forest birds recovery plan. USFWS, Portland, USA.

Scott, J. M.; Mountainspring, S.; Ramsey, F. L.; Kepler, C. B. 1986. Forest bird communties of the Hawaiian Islands: their dynamics, ecology, and conservation. Cooper Ornithological Society, California.

Pratt, H. D. 1994. Avifaunal change in the Hawaiian Islands, 1893-1993. Studies in Avian Biology 15: 103-118.

Loope, L. L.; Medeiros, A. C. 1995. Strategies for long-term protection of biological diversity in rainforests of Haleakala National Park and East Maui, Hawaii. Endangered Species Update 12: 1-5.

Herrmann, C. M.; Snetsinger, T. J. 1997. Pox-like lesions on endangered Puaiohi Myadestes palmeri and occurrence of mosquito Culex quinquefasciatus populations near Koaie Stream. 'Elepaio 57: 73-75.

Lepson, J. K.; Pratt, H. D. 1997. 'Akeke'e (Loxops caerulescens). In: Poole, A.; Gill, F. (ed.), The birds of North America, No. 295, pp. 1-14. The Academy of Natural Sciences and The American Ornithologists' Union, Philadelphia and Washington, DC.

Lepson, J. K. 1997. 'Anianiau (Hemignathus parvus). In: Poole, A.; Gill, F. (ed.), The birds of North America, No. 312, pp. 1-16. The Academy of Natural Sciences and The American Ornithologists' Union, Philadelphia and Washington, DC.

Holmer, S. 2007. Lear's Macaw making a remarkable comeback in protected reserve. AFA Watchbird 34(2): 8.

VanderWerf, E. A.; American Bird Conservancy. 2007. Petition to list the Akikiki or Kauai Creeper (Oreomystis bairdi) and the Akekee or Kauai Akepa (Loxops caeruleirostris) as endangered or threatened under the U.S. Endangered Species Act.

Further web sources of information
Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

Audubon WatchList

Click here for more information about the Alliance for Zero Extinction (AZE)

Hear sounds for this species from xeno-canto, the community database of shared bird sounds from around the world.

View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Capper, D., Derhé, M., Isherwood, I., Mahood, S., Stattersfield, A., Stuart, T., Symes, A., Taylor, J.

Contributors
Camp, R., Fretz, S., Gorresen, M., Roberts, P., VanderWerf, E., Woodworth, B.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2013) Species factsheet: Loxops caeruleirostris. Downloaded from http://www.birdlife.org on 25/05/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/05/2013.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

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