Justification of Red List Category
This species is listed as Critically Endangered because it has suffered extremely rapid annual population declines since 2003. The primary short-term driver of the decline is prolonged drought, which has reduced mamane pod production, but other contributing factors include habitat degradation by introduced ungulates, predation by introduced cats, and competition for caterpillar food from introduced parasitoid wasps.
Survey results from 2016 suggest that the population numbered c. 1,900 individuals, with the number of mature individuals estimated at 1,660 birds (C. Farmer in litt. 2016).
Between 2005 and 2010 the population fell from 5,337 birds to c. 1,200 birds (Leonard et al. 2008, American Bird Conservancy 2010). If we assume that the current decline continues for two generations into the future, the species is projected to experience a decline of over 95% over a three generation period.
This species is restricted to the island of Hawaii in the Hawaiian islands (U.S.A.), where it was abundant, although locally distributed, until the beginning of the 20th century, and evidence from the fossil record suggests that the species occurred throughout the archipelago prior to human settlement (Olson and James 1982, Burney et al. 2001). In 1997, it occupied an estimated 78 km2 and numbered 4,396 birds, mostly on the western slope of Mauna Kea, where 20.5 km2 was estimated to hold 72% of the total population (Scott et al. 1986, Fancy et al. 1997, Banko et al. 1998). Comparison of annual counts from 1980-2007 suggests that the population size has historically been subject to fluctuations (1,007-6,356 individuals) (Leonard et al. 2008), but since 2003 it has undergone a consistent and rapid decline (67% decline in the core population since 2003 and a linear projection of this decline indicates extinction by 2025) (R. Camp in litt. 2016, C. Farmer in litt. 2016). In 2016, the population was estimated at 1,934 individuals (R. Camp in litt. 2016). The species's range remains centered on the western slope, and it has contracted such that c.96% of the population is found in 4,600 ha of forest (R. Camp in litt. 2014). It has not been found in annual surveys on the east slope since 2004 (P. Banko in litt. 2007, C. Farmer in litt. 2007, R. Camp in litt. 2014, 2016). A small colony of reintroduced individuals has been extirpated on the northern slope (P. Banko et al. 2014a).
It is confined to altitudes of c. 2,000-3,000 m, favouring dry mamane and mamane-naio forest. It feeds primarily on mamane seeds, flowers, and insects (Banko et al. 2002a, Banko and Farmer 2014, Hess et al. 2014), with the availability of mamane seeds affecting productivity and adult survival. The species is morphologically and behaviourally adapted to feeding on mamane seeds, grasping pids with its feet and using its stout bill to tear them open. A recent study found that in both mamane woodland and mixed-woodland the species spent more time foraging on pods than flowers, but in mixed-woodland took more flowers than pods (Hess et al. 2014). In drought years, most birds do not attempt to breed (Jacobi et al. 1996, Pratt et al. 1997). The species exhibits low rates of reproduction (Banko et al. 2002a, Banko and Farmer 2012), laying fewer eggs and taking longer to raise its young compared with mainland songbirds (Hess and Banko 2006).
The most significant declines in this species's range and population are thought to have been caused by human-induced habitat loss and degradation and impacts from feral and domestic ungulates (Banko et al. 2002a, Banko and Farmer 2014, Banko et al. 2014b). The subalpine forest habitat of this species has been severely overbrowsed by sheep, mouflon sheep, goats, cattle, and its nests and adults are preyed upon primarily by feral cats, but also by introduced Black Rats Rattus rattus, Short-eared Owl Asio flammeus, and rarely Hawaiian Hawk Buteo solitarius (Banko et al. 2002a, Banko and Farmer 2014). Up to 11% of nests are depredated by feral cats each year (Hess and Banko 2006). Grazing by cattle was a historical factor in the species's decline, although cattle are now limited to pastures that are unsuitable for L. bailleui (C. Farmer in litt. 2007, Banko et al. 2014b). Alien grass cover is high in much of the species's range (Banko and Farmer 2014), suppressing mamane regeneration and potentially increasing the threat of fire (Thaxton and Jacobi 2009). Increasing human activities, such as military training, could further increase the chances of fire (Thaxton and Jacobi 2009). In 2006-2007, there were numerous fires on and near Mauna Kea, and fires in August and September 2010 affected c.560 ha of suitable habitat on the southern slope of the mountain (American Bird Conservancy 2010, Banko et al. 2014b). A fire in the species's core area could potentially affect >90% of the population. The opening of trails for all-terrain vehicles in the Mauna Kea Forest Reserve is a concern (C. Farmer in litt. 2007), and may cause disturbance and habitat degradation. Continuing threats include grazing by feral sheep, wild sheep Ovis gmelini musimon, and their hybrids, which slows mamane regeneration (Pratt et al. 1997, Banko and Farmer 2012, Banko et al. 2013, Banko et al. 2014b), and alien insects preying on and parasitising native insects (Pratt et al. 1997, Banko and Farmer 2012), particularly at low elevations (Banko and Farmer 2012). Native caterpillars are an important source of protein for nestlings, and possibly breeding females; however, they are preyed upon by Yellow-jacket Wasps Vespula pensylvanica and several ant species, particularly Argentine Ants Linepithema humile, whilst parasitoid wasps kill the caterpillars by laying their eggs on or inside them (Banko and Farmer 2012). In addition to the aforementioned threats, this species's very restricted range means it could be extirpated by extreme events such as drought and storms (Banko and Farmer 2012), and drought contributed to the species's recent decline (Banko et al. 2013). Demographic patterns of mamane mortality are under investigation, as mamane may be under threat from pathogens (USFWS 2006, Banko et al. 2014b). Climate change poses a long-term future threat to the species, as drought frequency and intensity are expected to increase at higher elevations, further affecting vegetation structure and compositions, and reducing the habitat's palila carrying capacity (Benning et al. 2002, Giambelluca and Luke 2007, Banko et al. 2013).
Conservation and Research Actions Underway
The species's population has been monitored since 1980 (Scott et al. 1986, Leonard et al. 2008, Camp et al. 2016). In 1979, 1987 and 1998, federal courts ordered the eradication of feral goats and feral and wild sheep species from the species's habitat on Mauna Kea, and these rulings have remained in effect despite six legal challenges (Banko et al. 2009, Banko et al. 2014b). Forest regeneration has improved as a result, although current efforts to reduce sheep have not been sufficient to allow the complete recovery of mamane forests (Banko et al. 2014b). Palila have some site fidelity, but have also been detected moving around Mauna Kea into new forested areas (Banko and Farmer 2014). In 1993, some birds were translocated to a new site on the eastern slope where predators were controlled and, although many homed back to their capture site, at least two pairs stayed and bred successfully (Fancy et al. 1997). Six additional translocations have taken place since, and by the end of 2006, 188 wild birds had been translocated from the western to the northern slope of Mauna Kea (Banko and Farmer 2014). Approximately 34% persisted for longer than two months, and a small colony of up to c.23 birds remained on the northern slope and bred successfully until 2010. Although F2 generation offspring were observed, the colony was not sustainable without additional management (Banko et al. 2009, Banko and Farmer 2014) and it was extirpated by 2011 (P. Banko in litt. 2012). Egg-laying occurred in 2004, and independent juveniles were produced in every year from 2005-2010 (Banko and Farmer 2014). This translocation programme was aided by a captive breeding programme initiated at the Keauhou Bird Conservation Center in 1996 (USFWS 2006, Banko and Farmer 2014). Of 28 captive-reared birds released in 2003-2009, at least 10 persisted in the reintroduction area for at least one year, with 2 males successfully producing fledglings with translocated wild females in the north slope colony before its extirpation (Banko and Farmer 2014).
The construction of a highway through unoccupied, federally designated critical habitat was approved in 1999. A mitigation plan accompanied the development, including the suspension of cattle grazing in pastures adjacent to the species's range on the northern and western slopes. The species's conservation was the subject of detailed research, and funding from the mitigation plan supported translocation research and enabled the expansion or continuation of studies into the species's ecology and limiting factors, mamane ecology, food availability, predator ecology and management, and fire ecology (Banko and Farmer 2014). The state of Hawaii continues habitat restoration and research into restoration methods (Banko and Farmer 2014). Work is being carried out to restore habitat by controlling fountain grass Pennisetum setaceum, which increases the frequency and intensity of fires, and Cape ivy Delairea odorata, which reduces the vigour of native trees (American Bird Conservancy 2010). The state of Hawaii has begun programmes to control cats and rats (Pratt et al. 1997, E. VanderWerf in litt. 1999, Banko and Farmer 2014). Goats have been removed from the mountain (C. Farmer in litt. 2007), and construction is underway to build 24.5km more fence which will then enclose the majority of Palila critical habitat. Once completed there will be 100.8km of fence preventing the ingress of sheep and goats, and allowing for forest recovery to occur naturally (G. Wallace in litt. 2009, American Bird Conservancy 2010). The fence is c. 2m high and encloses c. 94 % of the species's federally designated critical habitat. In 2010, a comprehensive fire management plan was being developed for the Mauna Kea area (Thaxton and Jacobi 2009, American Bird Conservancy 2010).
19 cm. Large finch with short, rounded bill. Male has golden-yellow head and breast surrounding black lores and bill, dark grey back and rump, white underparts, and dark wing and tail feathers with broad, golden edges. Female less golden and with grey of back extending forward on hindneck to crown. Similar spp. Introduced yellow morph of House Finch Carpodacus mexicanus has streaks on back and belly, yellow on rump. Introduced Yellow-fronted Canary Serinus mozambicus has grey nape, yellow underparts and rump, and bold facial markings. Both smaller. Voice Quiet, sweet canary-like song. Call a sweet chee-klee-o or pa-lee-la. Hints Best looked for at Pu'u La'au on Big Island.
Text account compilers
Benstead, P., Calvert, R., Capper, D., Derhé, M., Harding, M., Stattersfield, A., Stuart, T., Symes, A., Taylor, J., Khwaja, N., Wright, L & North, A.
Baker, H.C., Baker, P.E., Banko, P., Becker, D., Brinck, K., Camp, R., Farmer, C., Fretz, S., Gorresen, M., Leonard, D., Pratt, T., Scott, J., VanderWerf, E., Wallace, G. & Woodworth, B.
BirdLife International (2021) Species factsheet: Loxioides bailleui. Downloaded from http://www.birdlife.org on 21/09/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/09/2021.