Data Zone
Justification of Red List category
This species has a restricted range on one island where the population is thought to be declining and habitat degradation is ongoing. It is therefore assessed as Near Threatened.
Population justification
Estimates based on surveys of both the interior and exterior areas of the Alaka'i Plateau in 2018 placed the population at 51,903 individuals (95% CI: 29,203 – 76,403) (Paxton et al. 2020), roughly equivalent to 20,000-50,000 mature individuals overall.
Trend justification
The current population trend is increasing in the core of the range and decreasing in the periphery, suggesting that the range is contracting towards the core interior habitats of the Alaka‘i Plateau (Paxton et al. 2020). Within the three generations (15.7 years; Bird et al. 2020) to 2018, density increased in interior forest by c.36% and decreased in exterior forest by c.34%. Density estimates overall suggest a decline of c.7% within the three generations to 2018 (Paxton et al. 2020), and as such the population is estimated to be in slow decline. The rate of decline is placed in the range 5-10% within three generations.
Chasiempis sclateri is endemic to Kaua'i in the Hawaiian Islands (USA).
The species is most abundant in wet to mesic montane forest, also occurring in mesic woodland at lower densities. It feeds on insects and other invertebrates (Scott et al. 1986). In high-elevation native wet forests breeding begins at least by mid-February, and possibly earlier (Hammond et al. 2016). Both males and females incubate and brood and provision nestlings, with nests being placed in a variety of native trees including ‘Ōhi‘a, ‛Ōlapa, ‛Ōhelo, Alani, Kanawao, Kāwa‛u, and Lapalapa, with mean nest height being low compared to other native arboreal cup nesters on Kaua‛i at 5.1 ± 2.2 m SD (Hammond 2016). The species is better able to adapt to introduced forest dominated by non-native plant species than most native Hawaiian passerines (VanderWerf 2020).
Loss of native forest habitats to urbanisation, agriculture, and logging has decreased overall range in many areas (Scott et al. 1986). Diseases, such as avian pox and malaria, spread by mosquitoes, are a problem at all elevations, increasing mortality and possibly preventing birds from nesting (E. VanderWerf in litt. 1999, USFWS 2001, VanderWerf et al. 2006), although elepaios have greater immunity to introduced mosquito-borne diseases than most of the Hawaiian honeycreepers (VanderWerf 2020). Prevalence of mosquito-borne diseases is likely to increase with climate change (Atkinson et al. 2014). Habitat degradation as a result of invasive alien plants and ungulates is ongoing (Behnke et al. 2016, VanderWerf 2020). Avian predators include Hawaiian Short-eared Owl Asio flammeus sandwichensis and Barn Owl Tyto alba (VanderWerf 2020). Introduced mammalian predators are a further threat, such as feral cats (Felis catus) and rats (Rattus spp.), and the rate of nest depredation is higher in this species than in other forest species (Hammond et al. 2016). This species' restriction to Kaua'i also makes it vulnerable to catastrophic events such as hurricanes (P. Roberts in litt. 2007) which have caused substantial declines in the past (Pratt 1993, 1994).
Conservation Actions Underway
There are several protected areas within its range. This species has benefitted from conservation measured targeted at endangered honeycreepers on the island (VanderWerf 2012). Weed control has been conducted by The Nature Conservancy and Kōke‘e Resource Conservation Program (VanderWerf 2012). Since 2014, expanding grids of Goodnature A24 rat traps have protected nests and breeding birds in the core of its range (L. Crampton in litt. 2016). Ungulate-proof fences have been erected and are continuing to be erected in core habitat, and will help prevent further habitat degradation from weeds (L. Crampton in litt. 2016).
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 reddish-brown and have rufous wingbars (VanderWerf 2001). Adult grey above, white below, rusty-tinged breast has indistinct sooty border, white throat. Similar spp. Introduced Japanese Bush-warbler Cettia diphone duller with prominent eyebrow and no white markings. Introduced juvenile White-rumped Shama Copsychus malabaricus larger, darker above, with dark spots on breast and pink legs. Voice Song a lively whistled eh-leh-PYE-o, given in series of two or three with all phrases equally emphasised (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., Crampton, L., Roberts, P. & VanderWerf, E.
Recommended citation
BirdLife International (2024) Species factsheet: Kauai Elepaio Chasiempis sclateri. Downloaded from
https://datazone.birdlife.org/species/factsheet/kauai-elepaio-chasiempis-sclateri on 22/12/2024.
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 22/12/2024.