Justification of Red List category
This species has an extremely 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). The population trend appears to be stable, and hence 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, but the species is reported to be locally common (Baker 1997), while national population estimates include: c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in China; c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in Taiwan; c.10,000-100,000 breeding pairs and c.50-10,000 individuals on migration in Korea; < c.1,000 individuals on migration and < c.1,000 wintering individuals in Japan and c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Russia (Brazil 2009).
Trend justification
The population is suspected to be stable in the absence of evidence for any declines or substantial threats.
Text account compilers
Ekstrom, J., Butchart, S.
Recommended citation
BirdLife International (2024) Species factsheet: Dusky Warbler Phylloscopus fuscatus. Downloaded from
https://datazone.birdlife.org/species/factsheet/dusky-warbler-phylloscopus-fuscatus on 04/12/2024.
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 04/12/2024.