Justification This species qualifies as Vulnerable because it has a very small range. It occupies a small area of upland forest on one island, where it is at risk from the effects of exotic taxa. Although habitat is being degraded within its range, it apparently benefits from the introduction of banana poka and is able to utilise a broad range of habitat types.

Family/Sub-family Fringillidae

Species name author (Wilson, 1890)

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

Synonyms Viridonia stejnegeri Sibley and Monroe (1990, 1993), Viridonia stejnegeri Collar et al. (1994)

Identification 11 cm. Small honeycreeper with medium-sized, sickle-shaped bill. Male olive-yellow, brighter on head and underparts, with dark grey lores. Bill dark on culmen shading to bluish-grey base of mandible. Female and juvenile similar but less bright. Similar spp. `Anianiau H. parvus yellower, with much smaller bill and no black in lores. `Akeke`e Loxops caeruleirostris has shorter, bluish bill surrounded by dark mask, prominent yellow forehead and rump. Male Kaua`i Nukupu`u H. lucidus hanapepe yellow on head and breast, white below with all-black, thin bill, female nearly lacking yellow entirely. Voice Song a vigorous trill with short introductory note, sometimes on level pitch, sometimes descending. Typical call a sharp chirp. Also gives buzzy mewing note. Hints Bill much larger than in other `Amakihis, leading to many misidentifications as Nukupu`u. Easily seen at Koke`e.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

50,000-99,999

increasing

240 km²

Yes

Range & population Hemignathus kauaiensis is endemic to Kaua`i in the Hawaiian Islands (USA). It is common in the uplands including the Alaka`i Wilderness Preserve and especially in Kôke`e State Park, and an isolated population occurs in the Makaleha Mountains<sup>2,6,13</sup>. Historically it ranged down to coastal elevations, as indicated by fossil evidence<sup>14</sup>. During 1968-1973, surveys estimated the population at 10,743 (± 970 standard error), with 76% of the population in the "west of Alaka`i" study compartment¹³. Subsequent population estimates suggest that the population is greater than 15,000, possibly up to 20,000 birds, and increasing^4,5,10. In 1992, Hurricane Iniki devastated forests throughout Kaua`i and all bird populations on the island appeared to have been drastically reduced<sup>6,7</sup>. However, population estimates suggest that this species has recovered<sup>3,4,5,16</sup>, with the estimated population in the Alaka`i and Kôke`e areas increasing significantly to around 42,000 in 2000¹⁶.

Ecology: Originally, it occurred in native forests throughout Kaua`i. Today, it occurs above 600 m in `ohi`a forest, but is commonest in western koa-`ohi`a forest<sup>5,8,10,13</sup>. Preference for koa-`ohi`a may be attributable to koa itself², or the abundance of the introduced banana poka in the western parts of its range⁹. It feeds by gleaning insects from trunks and branches^5,8, and takes insects and nectar from flowers, apparently thriving on banana poka nectar^2,5,13. It is also an active excavator, hammering and flaking off bark to locate arthropods underneath¹².

Threats Clearance of the lowland forests on Kaua`i removed most of the habitat used by this species^5,13. Current threats include primarily threats introduced by humans, such as cats and rodent predators, competition from non-native birds (probably), disease (carried by introduced mosquitoes) and ongoing habitat degradation by ungulates and invasive plants^1,5,11,14. Increased temperatures and changes to altitudinal rainfall patterns anticipated as climate change progresses will likely lead to increased disease prevalence within remaining habitat¹⁵. High densities of this species in an area containing avian malaria suggests some level of resistance¹⁶. The restricted range of this species and dependence on canopy species makes it vulnerable to catastrophic events such as hurricanes¹⁴.

Conservation measures underway Its habitat is partially protected from development by the Alaka`i Wilderness Preserve and the Kôke`e State Park¹⁴, although so far there has been little or no active management for bird species in these protected areas¹⁷. This is changing, however, with the fencing of the top portion of the Alaka`i Wilderness Preserve, from within which ungulates will be removed¹⁷.

Conservation measures proposed Conduct long-term population monitoring⁵. Conduct research into its biology and limiting factors⁵. Control introduced plants, predators, herbivores, competitors and mosquitoes, especially in the Alaka`i Wilderness Preserve^5,10. Designate more native forests as legally protected⁵. Reforest some areas with native trees⁵.

References 1. P. Baker in litt. (1999). 2. Conant et al. (1998). 3. P. Donaldson in litt. (1999). 4. Jacobi and Atkinson (1995). 5. Lindsey et al. (1998). 6. Pratt (1993). 7. Pratt (1994). 8. Pratt et al. (1987). 9. Scott et al. (1985). 10. Scott et al. (1986). 11. J. M. Scott in litt. (1999). 12. T. Snetsinger in litt. (2000). 13. USFWS (1983). 14. P. Roberts in litt. (2007). 15. Benning et al. (2002). 16. Foster et al. (2004). 17. R. Camp in litt. (2007).

Further web sources of information

Audubon WatchList

Text account compilers Phil Benstead (BirdLife International), Isabel Isherwood (BirdLife International), Alison Stattersfield (BirdLife International), Tom Stuart (BirdLife International), Joe Taylor (BirdLife International)

Contributors Paul E Baker (US Fish & Wildlife Service), Rick Camp (US Geological Survey), Peter Donaldson, Scott Fretz (Hawaii Division of Forestry and Wildlife), Marcos Gorresen (US Geological Survey), David Leonard (Dept of Land and Natural Resources, Hawaii), Pauline Roberts (Hawaii Division of Forestry and Wildlife), J. Michael Scott, T Snetsinger, Eric VanderWerf (US Fish & Wildlife Service), Bethany Woodworth (US Geological Survey)

IUCN Red List evaluators Stuart Butchart (BirdLife International), Joe Taylor (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Hemignathus kauaiensis. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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