Data Zone
Justification of Red List category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Although the species is suspected of declining slowly, the species does not approach the thresholds for Vulnerable 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.
Population justification
The global population size has not been quantified, although its breeding range is large and the population size is accordingly not considered likely to be small.
Trend justification
Loss of its forest habitat in the breeding range is minimal (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein) and although is more extensive in its non-breeding range, here this species occurs in parkland and open forest types (eBird 2023). Consequently, although the species is precautionarily suspected of declining, it is thought to be doing so only very slowly.
Some aspects of this species' distribution remain enigmatic, principally due to difficulties in identifying silent birds (vs P. tenellipes) during the non-breeding season. It breeds in Sakhalin, Russia, as well as much of Japan (south to, and including, Honshu). Most birds migrate to South-East Asia (with a few wintering also in southern Japan), south to at least Peninsular Malaysia and Singapore. Has not yet been recorded in Indonesia (Eaton et al. 2021), but may occasionally stray there.
Text account compilers
Berryman, A.
Contributors
Butchart, S., Ekstrom, J. & Harding, M.
Recommended citation
BirdLife International (2024) Species factsheet: Sakhalin Leaf-warbler Phylloscopus borealoides. Downloaded from
https://datazone.birdlife.org/species/factsheet/sakhalin-leaf-warbler-phylloscopus-borealoides 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.