Data Zone
Justification of Red List category
This species has a restricted range where the loss and degradation of forest habitat is ongoing. It is therefore assessed as Near Threatened.
Population justification
The species is described as generally uncommon (Beichle and Maelzer 1985, del Hoyo et al. 2005, O'Brien and Masibalavu 2017), though numerous at some sites (Butler 2012). Based on point count data from 2016, the population has been estimated to number approximately 20,000 mature individuals (O'Brien and Masibalavu 2017).
Trend justification
This species is forest-dependent, and although remote sensing data are not available to detect current rates of forest loss (Global Forest Watch 2023, using data from Hansen et al. [2013] and methods disclosed therein), loss and degradation of forest habitat due to agricultural encroachment, logging and invasive species is thought to be ongoing (G. Dutson in litt. 2011, Butler 2012). Although the population trend has not been quantified directly, in 2017/18 surveys the species was recorded at only two of ten sites occupied two years previously (R. Stirnemann in litt. 2020). As such, tentatively, a continuing decline is inferred.
Lalage sharpei is endemic to Samoa where it is found on Savai'i (tenebrosa) and 'Upolu (nominate sharpei). There are some records from the Aleipata Islands, though here it is thought to be an infrequent visitor from the mainland (Parrish and Sherley 2012).
It primarily inhabits upland primary and secondary forest and forest edge. It rarely occurs in cattle pastures where there is undergrowth and trees, and in traditional plantations with few permanent houses (Beichle and Baumann 2003). It feeds on fruits and invertebrates (Beichle and Baumann 2003), foraging largely in the canopy of tall trees (Pratt and Mittermeier 2016).
It was presumably affected following cyclones Ofa and Val in 1990 and 1991, when canopy cover was significantly reduced (Elmqvist et al. 1994). Loss and degradation of forest habitat caused by agricultural encroachment, logging and invasive species are ongoing threats (G. Dutson in litt. 2011, Butler 2012). These threaten remaining areas of upland forest, as forestry roads from heavily logged lowland forests to allow access to formerly inaccessible land (Bellingham and Davis 1988, Butler 2012). In Pupu-pu'e National Park on `Upolu the species may be threatened by logging and cattle farming (Beichle and Maelzer 1985, Bellingham and Davis 1988). Rat predation may be a significant threat; the species was recorded at only two of ten previously occupied sites in 2017/18, with rat control ongoing at one of them (R. Stirnemann in litt. 2020).
Conservation Actions Underway
No targeted conservation actions for this species are known, however it occurs in multiple protected areas.
Conservation Actions Proposed
Conduct surveys to update information on density and distribution, and quantify the population size. Monitor population trends. Protect remaining suitable habitat. Control invasive species throughout the range.
Text account compilers
Vine, J.
Contributors
Dutson, G. & Stirnemann, R.
Recommended citation
BirdLife International (2024) Species factsheet: Samoan Triller Lalage sharpei. Downloaded from
https://datazone.birdlife.org/species/factsheet/samoan-triller-lalage-sharpei on 26/12/2024.
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 26/12/2024.