||Pseudonestor xanthophrys Rothschild, 1893
||del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
||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. Nukupuu Hemignathus lucidus 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 Akiapolaau Hemignathus munroi of Big Island. Hints Only accessible site for observers is Waikamoi Preserve, where rare but regular. Best located by voice.
|Red List Category & Criteria:
||Butchart, S. & Symes, A.
||Baker, H.C., Baker, P.E., Camp, R., Fretz, S., Gorresen, M., Lepson, J., Mounce, H., Pratt, T., Simon, J., VanderWerf, E., Woodworth, B. & Leonard, D.
||Benstead, P., Bird, J., Calvert, R., Derhé, M., Harding, M., Isherwood, I., Stattersfield, A., Stuart, T., Symes, A., Wright, L & North, A.
This species is listed as Critically Endangered because of its extremely small range. All of its range is fenced to protect from past degradation by introduced feral pigs, although deer now pose a new habitat threat. The species remains at risk from chance environmental events, such as hurricanes, as well as habitat degradation and the effects of exotic taxa.
|Previously published Red List assessments:|
- 2015 – Critically Endangered (CR)
- 2013 – Critically Endangered (CR)
- 2012 – Critically Endangered (CR)
- 2010 – Critically Endangered (CR)
- 2009 – Critically Endangered (CR)
- 2008 – Critically Endangered (CR)
- 2004 – Critically Endangered (CR)
- 2000 – Vulnerable (VU)
- 1996 – Vulnerable (VU)
- 1994 – Vulnerable (VU)
- 1988 – Threatened (T)
|Range Description:||This species is endemic to Maui in the Hawaiian Islands (U.S.A.), where it is found on the north-eastern slopes of Haleakala, although fossil evidence indicates that it once 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 m (Scott et al. 1986). Density surveys in 1997 and 2001 suggested similar numbers in the 35 km2 of remaining suitable habitat above 1,525 m (Simon et al. 1997, D. Leonard in litt. 2012), 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 stable (H. Mounce in litt. 2008). |
United States (Hawaiian Is.)
|♦ Continuing decline in area of occupancy (AOO):||Unknown|
|♦ Extreme fluctuations in area of occupancy (AOO):||No||♦ Estimated extent of occurrence (EOO) - km2:||49|
|♦ Continuing decline in extent of occurrence (EOO):||Unknown||♦ Extreme fluctuations in extent of occurrence (EOO):||No|
|♦ Number of Locations:||1||♦ Continuing decline in number of locations:||Unknown|
|♦ Extreme fluctuations in the number of locations:||No||♦ Lower elevation limit (metres):||1200|
|♦ Upper elevation limit (metres):||2150|
|Range Map:||Click here to open the map viewer and explore range.|
|Habitat and Ecology:||It is now restricted to montane mesic and wet forest at 1,200-2,350 m (mainly 1,500-2,100 m), and is absent from adjacent areas dominated by exotic trees (Mountainspring 1987, T. Pratt in litt. 1999, D. Leonard in litt. 2012). This habitat is probably marginal, as heavy rainfall leads to drastic losses during the breeding season (Simon et al. 2000). It feeds mainly on the larvae and pupae of wood- and fruit-boring beetles, moths and other invertebrates (Mountainspring 1987, Simon et al. 1997). Range size is 9.29 ha and territories are defended year-round (Pratt et al. 2001, Warren et al. 2015). 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 predators (Simon et al. 2000). During the breeding season (between November and June), one chick is usually raised per year and young are dependent on parents for 5-8 months (Lockwood et al. 1994, T. Pratt in litt. 1999, J. C. Simon in litt. 1999, Simon et al. 2000). Studies in the Hanawi Natural Area Reserve (NAR) in east Maui in 2006-2011 found nest success probability of 19 % (n=30) and seasonal nest success of 46 %, with 49 of 106 breeding pairs monitored successfully producing one fledgling (Mounce et al. 2013). |
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||4.5|
|Movement patterns:||Not a Migrant|
Conservation and Research Actions Underway
Life history and demographic studies have been on-going since 2005 (D. Leonard in litt. 2012), with genetic studies on- going since 1996 (Mounce et al. 2015). The East Maui watershed is cooperatively managed with fencing at c.1,070 m and removal of feral ungulates (Loope and Medeiros 1995, P. Baker in litt. 1999). In the Waikamoi Preserve, Hanawi Natural Area Reserve and Haleakala National Park, conservation practices additionally combat the establishment of alien plants and, since the late 1980s, feral pigs have been controlled (Loope and Medeiros 1995, Simon et al. 1997). As a result, the forest understory has recovered well and non-native plant invasions have slowed (Loope and Medeiros 1995, T. Pratt in litt. 1999). A small population exists in captivity, having bred for the first time in 2000 (Maxfield 2000), and numbered 12 individuals in 2015. Progeny from this flock will be used as part of a pilot release programme in the mesic forests of leeward East Maui where weather conditions may result in higher productivity (USFWS 2003). The Leeward Haleakala Watershed Restoration Partnership has been established to help restore the south side of Maui's forests in partnership with State agencies (H. Mounce in litt. 2008) and 1,100 ha of mesic koa forest is currently being restored on leeward east Maui (Mounce et al. 2014). 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 further suitable site for the establishment of a population (H. Mounce in litt. 2008). Experimental releases are planned in the next two years (Mounce et al. 2014).
Conservation and Research Actions Proposed
Carry out surveys to obtain an up-to-date estimate of the population size. Monitor population trends through regular surveys. Continue studies of life-history features (D. Leonard in litt. 2012). Due to their lower survival rates it has been suggested conservation measures focus on females and juveniles (Mount et al. 2014). Complete and routinely check ungulate exclusion fences (Stone and Loope 1987, Lockwood et al. 1994, Loope and Medeiros 1995, Simon et al. 1997). Conduct research to assess the impact of ungulate exclusion. Control alien plants, including outside the three wildlife protection areas (Loope and Medeiros 1995, Simon et al. 1997). Continue to replant koa forest in areas adjacent to its current distribution (Simon et al. 1997, Mount et al. 2014). Improve techniques for successful captive breeding and release. Begin public outreach concerning the importance and benefits of controlling rodents (D. Leonard in litt. 2012), and initiate rodent control at a landscape scale. Supplementary feeding may also aid species recovery (Mounce et al. 2014).