Hemignathus kauaiensis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Fringillidae

Scientific Name: Hemignathus kauaiensis
Species Authority: (Wilson, 1890)
Common Name(s):
English Kauai Amakihi, Kaua'i 'Amakihi
Viridonia stejnegeri stejnegeri Collar et al. (1994)
Viridonia stejnegeri stejnegeri Sibley and Monroe (1990, 1993)
Identification information: 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.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Baker, P.E., Camp, R., Donaldson, P., Fretz, S., Gorresen, M., Leonard, D., Roberts, P., Scott, J., Snetsinger, T., VanderWerf, E. & Woodworth, B.
Facilitator/Compiler(s): Benstead, P., Derhé, M., Isherwood, I., Stattersfield, A., Stuart, T., Taylor, J.
This species qualifies as Vulnerable because it has a very small range, occupying 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.

Previously published Red List assessments:
2008 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: 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 (USFWS 1983, Pratt 1993, Conant et al. 1998). Historically it ranged down to coastal elevations, as indicated by fossil evidence (P. Roberts in litt. 2007). 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 compartment (USFWS 1983). Subsequent population estimates suggested that the population was greater than 15,000, possibly up to 20,000 birds, and increasing (Scott et al. 1986, Jacobi and Atkinson 1995, Lindsey et al. 1998). In 1992, Hurricane Iniki devastated forests throughout Kaua`i and all bird populations on the island appeared to have been drastically reduced (Pratt 1993, 1994). However, population estimates suggest that this species has recovered (Jacobi and Atkinson 1995, Lindsey et al. 1998, P. Donaldson in litt. 1999, Foster et al. 2004), with the estimated population in the Alaka`i and Kôke`e areas increasing significantly to around 42,000 individuals in 2000 (Foster et al. 2004).

Countries occurrence:
United States
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 230
Continuing decline in extent of occurrence (EOO): Unknown
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
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population in the Alaka'i and Koke'e areas alone was estimated at around 42,000 individuals following surveys in 2000, thus the population is placed in the range band for 50,000-99,999 individuals.

Trend Justification:  The species's population in the Alaka`i and Koke`e areas increased significantly from around 11,000 individuals in 1973 to around 42,000 individuals in 2000 (Foster et al. 2004). The entire population is thus thought to be increasing.
Current Population Trend: Increasing
Additional data:
Continuing decline of mature individuals: No
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 2 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and 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 (USFWS 1983, Scott et al. 1986, Pratt et al. 1987, Lindsey et al. 1998). Preference for koa-`ohi`a may be attributable to koa itself (Conant et al. 1998), or the abundance of the introduced banana poka in the western parts of its range (Scott et al. 1985). It feeds by gleaning insects from trunks and branches (Pratt et al. 1987, Lindsey et al. 1998), and takes insects and nectar from flowers, apparently thriving on banana poka nectar (USFWS 1983, Conant et al. 1998, Lindsey et al. 1998). It is also an active excavator, hammering and flaking off bark to locate arthropods underneath (T. Snetsinger in litt. 2000).

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 5.5
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): Clearance of the lowland forests on Kaua`i removed most of the habitat used by this species (USFWS 1983, Lindsey et al. 1998). Current threats include primarily threats introduced by humans, such as cats and rodent predators, disease (carried by introduced mosquitoes), ongoing habitat degradation by ungulates and invasive plants and (probably) competition from non-native birds (Lindsey et al. 1998, P. Baker in litt. 1999, J. M. Scott in litt. 1999, P. Roberts in litt. 2007). Increased temperatures and changes to altitudinal rainfall patterns anticipated as climate change progresses, will likely lead to increased disease prevalence within remaining habitat (Benning et al. 2002). High densities of this species in an area containing avian malaria suggests some level of resistance (Foster et al. 2004). The restricted range of this species and its dependence on canopy species makes it vulnerable to catastrophic events such as hurricanes (P. Roberts in litt. 2007).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Its habitat is partially protected from development by the Alaka`i Wilderness Preserve and the Kôke`e State Park (P. Roberts in litt. 2007), although so far there has been little or no active management for bird species in these protected areas (R. Camp in litt. 2007). This is changing, however, with the fencing of the top portion of the Alaka`i Wilderness Preserve, from within which ungulates will be removed (R. Camp in litt. 2007).

Conservation Actions Proposed
Conduct long-term population monitoring (Lindsey et al. 1998). Conduct research into its biology and limiting factors (Lindsey et al. 1998). Control introduced plants, predators, herbivores, competitors and mosquitoes, especially in the Alaka`i Wilderness Preserve (Scott et al. 1986, Lindsey et al. 1998). Designate more native forests as legally protected (Lindsey et al. 1998). Reforest some areas with native trees (Lindsey et al. 1998).

Citation: BirdLife International. 2012. Hemignathus kauaiensis. The IUCN Red List of Threatened Species 2012: e.T22720756A39840429. . Downloaded on 29 November 2015.
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