Data Zone
Justification of Red List category
This species has a restricted range on one island where habitat degradation is ongoing and the population, though not especially small, is inferred to be in decline. It is therefore assessed as Near Threatened.
Population justification
The most recent total population estimate was 207,270 + 7,962 birds in 1986 (Scott et al. 1986, Gorresen et al. 2009), roughly equivalent to 140,000 mature individuals. There are three recognised subspecies, but variation in appearance is clinal and there is broad overlap (VanderWerf 2011). Population estimates for each subspecies are as follows: bryani c.2,500 birds in 1983; sandwichensis c.63,000 birds in 1983; and ridgwayi c.150,000 birds in 1976-1979 (Scott et al. 1986).
Trend justification
Surveys in the Central Windward region of Hawai`i from 1977 to 2003 indicate that the species was stable at high elevations and declining at low elevations (Gorresen et al. 2005). Since the 1980s density has decreased in leeward and mid-elevation windward areas (Gorresen et al. 2009). There is also evidence of a decline in the Ka`u region between 1976 and 2005 (Tweed et al. 2007). Its disappearance from Pohakuloa Training Area was recently noted (VanderWerf 2011), and declines have been detected in high elevation mamane-naio forests (E. VanderWerf in litt. 2011). In Pu‘u ‘O ‘Umi Natural Area Reserve on Kohala, surveys in 1979 and 2017 indicated a density decline of 8.4% (Burnett et al. 2021). Additionally, the species declined in the proportion of stations detected during 1998–2011 surveys in subalpine woodland habitat on Mauna Kea Volcano (Banko et al. 2013). A recent analysis of annual population density estimates in Hakalau Forest National Wildlife Refuge, with this region supporting 14% of the global population, showed that trends were inconclusive across all strata (open forest, closed forest and pasture) in the most recent decade 2010-2019 (Kendall et al. 2022). However density in closed forest alone declined by approximately 25% in the last three generations (Kendall et al. 2022). Given that the threats to this species have not ceased, the population is precautionarily inferred to be declining overall although the rate has not been quantified.
This species is endemic to Hawai'i in the Hawaiian Islands (USA).
Subspecies bryani occupies arid, mostly high-altitude mamane and mamane-naio woodland, whilst sandwichensis occurs in mesic habitats on western and south-western slopes, and ridgwayi is restricted to wet, eastern slopes (Pratt 1980, Scott et al. 1986, VanderWerf 1998). It feeds on insects and other invertebrates (Scott et al. 1986).
Loss of native forest habitats to urbanisation, agriculture and logging has decreased the overall range in many areas (Scott et al. 1986). The habitat of bryani has been heavily browsed by feral ungulates, and introduced grasses suppress regeneration and potentially increase the risk of fire (Scott et al. 1986). Density is lower in disturbed forest, and ungulates, invasive introduced plants and climate change are thought to be causing declines in habitat quality within the range (VanderWerf 2012, Banko et al. 2013, USFWS 2020). Diseases, such as avian pox and malaria, spread by mosquitoes, are a problem at low and middle elevations, increasing mortality and possibly preventing birds from nesting (E. VanderWerf in litt. 1999, VanderWerf et al. 2006), although elepaios have greater immunity to introduced mosquito-borne diseases than most of the Hawaiian honeycreepers (VanderWerf 2020). Current avian predators include Hawaiian Hawk Buteo solitarius, Hawaiian Short-eared Owl Asio flammeus sandwichensis and Barn Owl Tyto alba (VanderWerf 2020). Introduced mammalian predators including rats, cats Felis catus and mongooses Herpestes auropunctatus are additional threats (Banko et al. 2019, VanderWerf 2020). It has been suggested that the species may also suffer increased mortality associated with infection by chewing lice (Phthiraptera) (Freed et al. 2008). It remains vulnerable to future catastrophic events such as hurricanes (E. VanderWerf in litt. 2012).
Conservation Actions Underway
This species has benefitted from conservation measured targeted at endangered honeycreepers on the island, particularly habitat protection and management (VanderWerf 2012, 2020). Hakalau Forest National Wildlife Refuge, Hawaii Volcanoes National Park, Ka‘u and Kapapala forest reserves. Ola'a-Kilauea Management Area and the Pu'u Wa'awa'a State Forest Bird Sanctuary protect areas of important habitat for endangered honeycreepers and other forest birds (VanderWerf 2020). Restoration and management actions include fencing, ungulate eradication, limited predator control, forest restoration, and habitat monitoring (VanderWerf 2020). Control of invasive Black Rats has resulted in increased nesting success of Hawaii Elepaio (Banko et al. 2019).
14 cm. Small monarch flycatcher that often cocks its tail. Adults have white tips to tail feathers, white rump, and white wing bars. Immatures are greyish-brown and have buffy wingbars (VanderWerf 2001). Adult variable and sexually dimorphic, generally brown above with white underparts and variable amount of dark streaking below; male has black chin, female white (VanderWerf 2001). Similar spp. Introduced Japanese Bush-warbler Cettia diphone duller with prominent eyebrow and no white markings. Voice Song a lively whistled eh-leh-PYE-o, given in series of four with emphasis on the third phrase (del Hoyo et al. 2006); calls include sharp chup, two-note squeak-it like dog's toy, and raspy chatter.
Text account compilers
Vine, J.
Contributors
Camp, R. & VanderWerf, E.
Recommended citation
BirdLife International (2024) Species factsheet: Hawaii Elepaio Chasiempis sandwichensis. Downloaded from
https://datazone.birdlife.org/species/factsheet/hawaii-elepaio-chasiempis-sandwichensis on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.