Justification This species is classified as Endangered because it has a very small, severely fragmented range, and is experiencing continuing declines in range, habitat quality and population, largely owing to the effects of introduced species. It is projected that the extirpation of small subpopulations will continue.

Family/Sub-family Fringillidae

Species name author (Rothschild, 1893)

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

Synonyms Hemignathus wilsoni Sibley and Monroe (1990, 1993), Hemignathus wilsoni Collar et al. (1994)

Identification 14 cm. Stocky, bull-headed honeycreeper with peculiar mismatched bill. Long and decurved maxilla, straight mandible half the length of maxilla, leaving small diastema in closed bill. Male yellow-green dorsally, yellow ventrally, with orange tinge to face and upper breast, whitish tinge to undertail-coverts. Similar spp. Hawai`i `Amakihi H. virens similarly coloured but much smaller with proportionally smaller bill. Voice Song a short, rapid warble. Calls include an upslurred whistle, a very short warble cheedle-ee, and a short sweet. Juveniles utter loud chewp as sound beacon to attendant adults. Hints Can still be found in forest tracts off Saddle Road and Hakalau Forest National Wildlife Refuge. Usually in small family groups.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,200

decreasing

150 km²

Yes

Range & population Hemignathus munroi is endemic to Hawai`i in the Hawaiian Islands (USA), where it was formerly widespread. In 1976-1979 and 1983, surveys estimated c.1,500 birds, with 900 in Hamakua, 500 in Ka`u, 50 on Mauna Kea, and 20 in central Kona⁶. In 1990-1995, surveys estimated 1,163, representing a decline of c.22.5% over 13 years, with 1,105 in Hamakua (fragmented into two, possibly four, distinct subpopulations at Keauhou-Kulani, c.312 birds, and north Hamakua, c.793 birds), c.44 in Ka`u, fewer than 10 on Mauna Kea (and only a few males by 1999<sup>4</sup>), and perhaps fewer than 10 in Kona<sup>1</sup>. The Mauna Kea population became extinct in 2002 and the species has not been seen in Kona since the late 1990s<sup>12</sup>. Surveys from 1977 to 2003 indicate that the species may have declined in the Kûlani-Keauhou area<sup>15</sup>. In the Ka`u District of Hawai`i, surveys from 1976 to 2005 indicate that the species has been extirpated from habitat below 1,500 m, with no change in the density of populations at high elevations<sup>16</sup>. The species's population in Ka`u was estimated at 1,073 indviduals (95% CI: 616-1,869) in 2005¹⁶.

Ecology: It occurs mainly in old-growth mesic and wet koa Acacia koa and `ohi`a Metrosideros polymorpha forest between 1,300 and 2,100 m in Ka`u, Hamakua and perhaps still in Kona<sup>5</sup>. It formerly occupied dry mamane and naio woodlands from 1,900 to 2,900 m on Mauna Kea<sup>5,12</sup>. Recent research suggests that it occurs in high densities and forages and nests successfully in secondary growth koa in regenerating forests<sup>4,11</sup>. The species is found at its highest densities in koa plantations and forests with a high percentage of koa trees<sup>11</sup>. It is the only species on Hawai`i to exploit the woodpecker niche, but is rare despite the lack of competition⁵. It feeds primarily on lepidopteran and cerambicid larvae under the bark of koa trees, and it only occasionally feeds on nectar¹⁰. Its preference for koa trees is evident despite the relative scarcity of this tree species in the environment¹¹. As an apparent alternative to nectar the species regularly feeds on sap from `ohi`a trees all year round, perhaps to supplement insect larvae, whose populations fluctuate. The species acquires sap by drilling 3-5 mm deep holes into the phloem of suitable trees and drinking the sap that emerges. The preferred trees (known as "Aki trees") are rare (2 ha^-1), spatially clustered and defended by the species. Selected trees are probably used by successive generations¹⁰. Pairs occupy very large home ranges (0.25-0.30 km²)⁷ and produce only one chick per year¹³, which has a long dependency period⁵.

Threats The chief threats are thought to be habitat modification through grazing and logging (particularly of koa), predation by introduced rats, feral cats and native raptors, and avian diseases spread by introduced mosquitoes, which restrict it to high altitude⁵. Predators may have been the primary threat to the now extinct Mauna Kea population, while disease may be responsible for declines in protected areas¹. Due to its low reproductive rate this species may be particularly vulnerable to these threats and slow to recover⁹.

Conservation measures underway Populations occur within Ka`u Forest Reserve, the Keauhou Ranch, Olaa/Kilauea partnership area, Kapapala Forest Reserve, Hakalau Forest National Wildlife Refuge<sup>1,2,12,13</sup> and the Kahuku Unit of Hawai`i Volcanoes National Park (acquired in 2003)¹⁴. Habitat restoration work is underway for this species⁸. Removal of sheep and mouflon from Mauna Kea has permitted regeneration of mamane forest habitat⁹. However, the species is now extinct there^12,13. Removal of cattle and fencing of the Kapapala Forest Reserve and the Pu`u Wa`awa`a Forest Bird Sanctuary has occurred; although the species does not occur in the latter reserve, it could serve as a site for reintroduction⁹. The removal of cattle, mouflon and pigs from the Kahuku Unit of the national park is expected to benefit the species¹³. Extensive replanting of koa has occurred at Hakalau Forest National Wildlife Refuge (~ 4,000 ha) and on Keauhou Ranch^11,12,13. Both sites have been fenced and ungulates have been removed from significant portions of each site¹².

Conservation measures proposed Conduct ecological research, including demography in different habitat types, partly in preparation for reintroduction to unoccupied restored habitat⁴. Investigate how to protect and restore habitat effectively at a landscape level, connecting fragmented populations, and publish the results as an action plan. Conduct research into the impact of alien insect competition for invertebrate food resources³. Protect remaining old-growth `ohi`a and koa forests above the zone where mosquitoes occur⁵. Remove feral ungulates from remaining high elevation and old growth forests to allow natural regeneration and possibly increase density of H. munroi populations^9,13. Replant koa on exotic grasslands, such as extensive pastures in protected areas, at high elevations (above the disease line)^11,13. Develop captive propagation techniques to help speed recovery⁹. Ensure that protected areas include an adequate number of preferred sap trees ("Aki trees")¹⁰. Incorporate the need for a supply of suitable sap trees¹⁰ into long-term habitat restoration efforts. Monitor the species's populations in new koa plantations that are replacing exotic grasslands in Hakalau Forest National Wildlife Refuge¹¹. Work with land-owners to combine habitat restoration and the commercial growing of koa trees¹¹.

References 1. Fancy et al. (1996). 2. J. Lepson in litt. (1999). 3. M. Morin in litt. (1999). 4. T. Pratt in litt. (1999). 5. Ralph and Fancy (1996). 6. Scott et al. (1986). 7. E. VanderWerf in litt. (1999). 8. S. Fretz, E. Vanderwerf, R. Camp, M. Gorresen and B. Woodworth in litt. (2003). 9. USFWS (2003). 10. Pejchar and Jeffrey (2004). 11. Pejchar et al. (2005). 12. L. Pejchar in litt. (2007). 13. T. Pratt in litt. (2007). 14. Tweed et al. (2007). 15. Gorresen et al. (2005). 16. Gorresen et al. (2007).

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), Matt Harding (BirdLife International), Isabel Isherwood (BirdLife International), Alison Stattersfield (BirdLife International), Tom Stuart (BirdLife International), Joe Taylor (BirdLife International)

Contributors Rick Camp (US Geological Survey), Scott Fretz (Hawaii Division of Forestry and Wildlife), Marcos Gorresen (US Geological Survey), Jaan Lepson, Marie Morin (US Fish & Wildlife Service), Liba Pejchar (Stanford University), Thane Pratt (US Geological Survey), 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 munroi. 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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