Justification of Red List Category
Although this species may have a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 or area of occupancy <2,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The population size of this species has not been quantified; it is considered uncommon to common.
The population trend is difficult to determine because of uncertainty over the impacts of habitat modification on population sizes.
This species is found in Palau, as well as Pohnpei and Chuuk, Federated States of Micronesia (see van Balen 2017). Tracewski et al. (2016) estimated the maximum area of occupancy (calculated as the remaining tree area within the species’s range) to be c.544 km2, rounded here to 540 km2.
Text account compilers
Butchart, S., Westrip, J., Symes, A., Ekstrom, J.
BirdLife International (2019) Species factsheet: Zosterops semperi. Downloaded from http://www.birdlife.org on 11/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 11/11/2019.