Data Zone
Justification of Red List category
This species has a very restricted range on a single island where there is thought to be an ongoing decline in habitat quality. It is therefore assessed as Near Threatened.
Population justification
The population size has not been quantified, but the species is described as common within its small range (Butler 2012, Pratt and Mittermeier 2016). It is frequently encountered in small flocks, most commonly in the more modified open forests above Asau, and its presence in 38% of 30-minute surveys including 65% at Asau suggests that it is present in good numbers (Butler 2012).
Trend justification
There are no data on population trends; however, the population is suspected to be stable in the absence of evidence for declines or substantial threats. Remote sensing data are not available to estimate the rate of tree cover loss within the range (Global Forest Watch 2023, using data from Hansen et al. [2013] and methods disclosed therein), however the forests of upland Savai'i are considered well preserved and the species appears to be relatively secure (Butler 2012, Pratt and Mittermeier 2016).
Zosterops samoensis is endemic to Savai'i, Samoa.
It occurs in the highlands mainly above 900 m where it has been recorded in flocks of 15-20 birds in the canopy of prime upland forests, but has been recorded as low as 780 m, and also in open scrub-like alpine habitat and secondary scrub on the Mata o le Afi lava flow where it forages in low bushes up to several hundred meters from the forest edge (Bellingham and Davis 1988, S. Ericsson in litt. 1994, Pratt and Mittermeier 2016). It is frequently encountered in small flocks, most commonly in the more modified open forests above Asau (Butler 2012). Observations suggest it may conduct daily or seasonal movements between different elevation zones (Butler 2012).
Although the species is considered to be secure overall, the uplands still contain many of the same threats that affect the lowlands: invasive species including weeds, rats, feral pigs and cattle are present and likely causing ongoing habitat degradation (Butler 2012). Remaining areas of upland forest may continue to be threatened as forestry roads from heavily logged lowland forests provide access to formerly inaccessible land (Bellingham and Davis 1988, Butler 2012). For example, the illegal bulldozed road from A’opo to Mata o le Afi opens up a pathway for the introduction of new weeds and other invasive species to the upland forest, as well as the potential for logging (Butler 2012). The diversity and prevalence of invasive species in upland forests may be increasing over time as invasive species slowly spread into less degraded forest and as forest slowly degrades uphill (J. Pilgrim in litt. 2023). Invasive wasp and ant species may affect native invertebrate populations, impacting this species and other insectivores/generalists in the longer term (J. Pilgrim in litt. 2023).
Conservation Actions Underway
Mt Silisili Park, a unique area of montane cloud-forest in central Savai`i, is a refuge for the species (Beichle and Maelzer 1985). Portions of its range are included within three protected areas (UNEP-WCMC and IUCN 2023).
10 cm. Small, warbler-like bird. Olive-green above, dingy white below with yellow tinge to throat and conspicuous, completely white eye-ring. Pale iris. Voice a high-pitched tchee or cheeer sound, occasionally with a gurgling or buzzy quality (Pratt and Mittermeier 2016). Hints Moves about in small flocks.
Text account compilers
Vine, J.
Contributors
Ericsson, S. & Pilgrim, J.
Recommended citation
BirdLife International (2024) Species factsheet: Samoan White-eye Zosterops samoensis. Downloaded from
https://datazone.birdlife.org/species/factsheet/samoan-white-eye-zosterops-samoensis on 23/12/2024.
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 23/12/2024.