Justification This species is listed as Critically Endangered because habitat within its extremely small range is being seriously degraded by introduced feral ungulates. Much of its range is now fenced so may be adequately protected from this threat, although the species remains at risk from chance environmental events, such as hurricanes, habitat degradation and the effects of exotic taxa.

Family/Sub-family Fringillidae

Species name author Rothschild, 1893

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

Identification 14 cm. Chunky, short-tailed, big-headed passerine with huge parrot-like bill. Male olive-green above, yellow below with dark streak through eye and bold, sharply defined yellow superciliary. Two-toned bill, upper third of maxilla dark, remainder pale yellowish-pink. Female duller with much smaller bill. Similar spp. Maui Nukupu`u Hemignathus lucidus affinis has yellow head without dark eye-line and bold superciliary, and much thinner bill. Voice Song a plaintive series of short whistles descending in pitch chwee-chwee-chwee-chwee-chwee. Calls include short warble, upslurred whistle, and loud chewp uttered by dependent juveniles, all similar to calls of `Akiapola'au Hemignathus munroi of Hawai`i. Hints Only accessible site for observers is Waikamoi Preserve, where rare but regular. Best located by voice.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

500

decreasing

50 km²

Yes

Range & population Pseudonestor xanthophrys is endemic to Maui in the Hawaiian Islands (USA), where it is found on the north-eastern slopes of Haleakala, although fossil evidence indicates that it occurred in the lowlands and on Moloka`i. During 1976-1983, it was estimated to number c.500 individuals, of which 71% (c.355) occurred above 1,500 m⁹. Density surveys in 1997 suggested similar numbers in the 35 km² of remaining suitable habitat above 1,525 m¹⁰, and the number of birds detected on point counts since 1980 has not altered significantly, but further work is needed to confirm whether the population has genuinely remained stable¹⁸.

Ecology: It is now restricted to montane mesic and wet forest at 1,200-2,150 m (mainly 1,500-2,000 m), and is absent from adjacent areas dominated by exotic trees^6,8. This habitat is probably marginal (heavy rainfall leads to drastic losses during the breeding season)¹⁴. It feeds mainly on the larvae and pupae of wood- and fruit-boring beetles, moths and other invertebrates^6,10. Range size is c.2.26 ha and territories are defended year-round¹⁵. The nest is cup-shaped and placed in the outer canopy forks of mature ohia (Metrosideros polymorpha) - a situation that may afford some protection from introduced predators¹⁴. During the breeding season (November to June), one chick is usually raised per year and young are dependent on parents for 5-8 months^4,8,11,14.

Threats From 1945 to 1995, the invasion of feral pigs on Haleakala caused chronic habitat degradation⁵ and facilitated the spread of disease-carrying mosquitoes into remote rainforests⁷. Most of the species's range is now fenced however, and the species may respond positively as a result. Weather influences the survival of young and thus potential recruitment rates¹⁰. Other limiting factors include predation and competition from exotic bird and insect species^6,10. Rats have been observed high in native 'olapa trees and are both a potential predator of eggs and young and a potential source of competition for berries¹⁷.

Conservation measures underway The East Maui watershed is cooperatively managed with 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 additionally combat the establishment of alien plants and, from the late 1980s, feral pigs have been controlled^5,10. As a result, the forest understorey has recovered well and non-native plant invasions have slowed^5,8. Rats are being poisoned³, although only in a tiny area². A small population exists in captivity and, having bred for the first time in 2000¹³, now numbers ten (three males and seven females)¹⁶. Progeny from this flock will be used for a pilot release programme in the mesic forests of leeward East Maui where weather conditions may result in higher productivity¹⁶. The Leeward Haleakala Watershed Restoration Partnership has been established to restore the south side of Maui's forests, and the State of Hawaii is working on fencing the leeward side which still contains some old growth koa - it is possible this may become a suitable site for the establishment of a second population¹⁸.

Conservation measures proposed Carry out surveys to obtain an up-to-date estimate of the population size. Monitor population trends through regular surveys. Complete and routinely check ungulate exclusion fences^4,5,10,12. Conduct research to assess the impact of ungulate exclusion. Complete ungulate eradication programme^1,5. Control alien plants, including outside the three wildlife protection areas^5,10. Continue to replant koa forest in areas adjacent to its current distribution¹⁰. Improve techniques for successful captive breeding and release.

References 1. P. Baker in litt. (1999). 2. H. Baker and P. Baker in litt. (2000). 3. J. Lepson in litt. (1999). 4. Lockwood et al. (1994). 5. Loope and Medeiros (1995). 6. Mountainspring (1987). 7. Pratt (1994). 8. T. Pratt in litt. (1999). 9. Scott et al. (1986). 10. Simon et al. (1997). 11. J. C. Simon in litt. (1999). 12. Stone and Loope (1987). 13. Maxfield (2000). 14. Simon et al. (2000). 15. Pratt et al. (2001). 16. USFWS (2003). 17. Maui Forest Bird Recovery Project (2008). 18. H. Mounce in litt. (2008).

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

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), Andy Symes (BirdLife International)

Contributors Helen C. Baker (US Fish & Wildlife Service), Paul E Baker (US Fish & Wildlife Service), Rick Camp (US Geological Survey), Scott Fretz (Hawaii Division of Forestry and Wildlife), Marcos Gorresen (US Geological Survey), Jaan Lepson, Hanna Mounce (Maui Forest Bird Recovery Project), Thane Pratt (US Geological Survey), J. C Simon, Eric VanderWerf (Pacific Rim Conservation), Bethany Woodworth (US Geological Survey)

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

Recommended citation BirdLife International (2009) Species factsheet: Pseudonestor xanthophrys. Downloaded from http://www.birdlife.org on 9/2/2010

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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