Akohekohe - BirdLife Species Factsheet

Justification This species is listed as Critically Endangered because habitat within its extremely small range is being degraded through grazing by feral goats, with an imminent threat from feral deer posing a new pressure. It remains at risk from the effects of exotic taxa. A particular concern is the possible introduction of a disease-carrying mosquito species tolerant of the cooler climate at higher altitudes, thereby bringing currently safe populations of birds into contact with lethal diseases.

Family/Sub-family Fringillidae

Species name author (Wilson, 1891)

Taxonomic source(s) AOU checklist (1998 + supplements), Sibley and Monroe (1990, 1993)

Identification 18 cm. Large honeycreeper with slightly downcurved, sharp bill and distinctive forward-curving crest of stiff, white feathers on forehead. Mostly black, streaked and spotted with orange-red and silvery-grey. Shaggy red-orange patch on hindneck, orange-buff eye-ring and short postocular stripe. Orange-buff thighs. Primaries and tail feathers tipped white. Sexes similar, but juvenile all sooty-grey with orange-buff eye-ring and very short, grey crest. Voice Song a variable series of low-pitched notes ah-gurk-gurk-gurk or ah-koh-heh-koh-heh and many other variations. Call a human-like upslurred whistle.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

3,750

decreasing

60 km²

Yes

Range & population Palmeria dolei occurs on Maui in the Hawaiian Islands (USA) and is extinct on Moloka`i (last confirmed observations in 1907). On Maui, it remains moderately common within 58 km² on the north-eastern slopes of Haleakala, with a population estimated at c.3,800 birds in 1980⁸. Surveys in the 1990s to 1997 indicate stability, although areas outside protected areas were not necessarily covered^3,4.

Ecology: It occurs in mesic `ohi`a-koa and wet `ohi`a forest from 1,100-2,300 m (99% above 1,500 m, mostly below 2,100 m). It primarily feeds on `ohi`a nectar, also taking invertebrates, especially caterpillars. When `ohi`a bloom is at its seasonal low, it feeds on subcanopy and understory flowers and fruit^1,2,8,11. Average adult male home range is 0.56 ha, giving rise to density figures of 2.9 birds/ha¹⁴. All known nests have been in `ohi`a trees³. It raises 1-2 young per nest, usually nesting twice seasonally (November to June¹³), and has a relatively high success rate^11,13. Adult survivorship is similarly high¹³. Birds, perhaps especially immatures, may disperse to lower elevations³.

Threats Habitat destruction and modification and the rapid spread of disease-carrying mosquitoes in the lowlands are thought to be responsible for past declines. The species may be particularly vulnerable to mosquito-borne diseases because it migrates altitudinally in response to varying `ohi`a flowering physiology, potentially increasing exposure to mosquitoes at lower elevations¹⁵. From 1945 to 1995, the spread of feral pigs on Haleakala caused chronic habitat degradation⁵ and facilitated the spread of mosquitoes into remote rainforests⁶. In Hanawi Natural Area Reserve, there was a 473% increase in pig activity, as indexed by ground-cover disturbance, during 1970-1997⁷, and this reduced alternative food sources to `ohi`a bloom³. Predation by introduced rats, cats and Barn Owl Tyto alba and possibly small Indian mongoose Herpestes auropunctatus is a further limiting factor^3,9,11,12.

Conservation measures underway Cooperative management of the East Maui watershed includes fencing at c.1,070 m and removal of feral ungulates^1,5. In the Waikamoi Preserve, Hanawi Natural Area Reserve and Haleakala National Park, conservation practices combat the establishment of alien plants and, from the late 1980s, feral pigs have been controlled^5,10. Research into captive breeding is underway, and six individuals have been hatched from late-stage wild eggs¹⁵.

Conservation measures proposed Carry out surveys to obtain an up-to-date estimate of the population size. Monitor population trends through regular surveys. Preserve remote and ecologically diverse areas, especially on the northern slopes of Haleakala³. Extend plant control to areas outside reserves, especially at mid-elevations^5,10. Complete and routinely monitor the East Maui watershed habitat conservation programme^1,11. Establish a population in historically occupied habitat to reduce the threat from catastrophes that could wipe out a single population¹⁵. Continue monitoring of captive-breeding efforts.

References 1. P. Baker in litt. (1999). 2. Berger (1972). 3. Berlin and VanGelder (1999). 4. Jacobi and Atkinson (1995). 5. Loope and Medeiros (1995). 6. Pratt (1994). 7. Rosa et al. (1998). 8. Scott et al. (1986). 9. J. M. Scott in litt. (1999). 10. Simon et al. (1997). 11. J. C. Simon in litt. (1999). 12. E. VanGelder in litt. (1999). 13. Simon et al. (2001). 14. Pratt et al. (2001). 15. USFWS (2003).

Further web sources of information

Audubon WatchList

U.S. Fish and Wildlife Service - Revised Recovery Plan for Hawaiian Forest Birds 2006

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Matt Harding (BirdLife International), Isabel Isherwood (BirdLife International), Alison Stattersfield (BirdLife International), Tom Stuart (BirdLife International)

Contributors Rick Camp (US Geological Survey), Scott Fretz (Hawaii Division of Forestry and Wildlife), Marcos Gorresen (US Geological Survey), Eric VanderWerf (US Fish & Wildlife Service), Bethany Woodworth (US Geological Survey)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2008) Species factsheet: Palmeria dolei. Downloaded from http://www.birdlife.org on 3/1/2009

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, and BirdLife International (2004) Threatened birds of the world 2004 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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