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 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 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.
No population estimate has been made, however the species is the result of merging two species that were common in much of their range and so it is likely to have a very large global population.
The population trend of this species is unknown, however it is not thought to be decreasing sufficiently rapidly for the species to be threatened.
This species has a large range. The subspecies whiteheadi, halconensis, parkesi, pectoralis, diutiae and volcani are present in the Phillipines (van Balen 2019a). Subspecies obstinatus, dificilis and montanus are present in Indonesia; montanus is also present in Timor-Leste (van Balen 2019b). Subspecies japonicus, insularis, loochooensis, daitoensis, stejnegeri and alani are present in Japan; japonicus is also present in the southern part of South Korea (van Balen 2019a).
There are 15 subspecies within the Mountain White-eye (Zosterops japonicus). These are: whiteheadi, halconensis, parkesi, pectoralis, diutiae, volcani, difficilis, montanus, obstinatus, japonicus, insularis, loochooensis, daitoensis, stejnegeri and alani.
The subspecies whiteheadi, halconensis, parkesi, pectoralis, diutiae, volcani, difficilis, montanus and obstinatus usually occupy primary montane or moss forest, as well as ericaceous shrubs, forest edge, secondary growth, and in isolated bushes almost up to barren mountain summits, or as high as the fumes, fires and eruptions of volcanoes permit vegetation to approach. On Timor, Java and Luzon islands they also occupy casuarina (Casuarina) stands and pine (Pinus) forests. On Sumbawa island, they can be found in dodonaea shrubs, and on Flores island, in wooded cultivation. These subspecies are generally found no lower than 500 m, generally above 900–1,200 m; above 1,000 m in Philippines, 2,200–3,100 m in Sumatra, 1,600–3,300 m in Java, 1,500–3,500 m (occasionally down to 900 m) on Sulawesi; fairly common between 1,000 m and 1,300 m, common above 1,000 m to at least 2,300 m on Sumbawa, scarce at 2,300 m on Seram. The lowest mountain on Java on which it is known to occur is Mt Papandayan (2,660 m) (van Balen 2019a).
The subspecies japonicus, insularis, loochooensis, daitoensis, stejnegeri and alani occupy deciduous or mixed forests, thickets, open woodland, secondary growth, and also cultivated areas (e.g. urban parks, gardens, farmlands, groves, orchards). They can be found in tall forest trees in winter. They mostly breed in lowlands, but occur up to c. 1,000 m (van Balen 2019b).
This species may be being trapped for the cage-bird trade.
Text account compilers
Elliott, N., Martin, R., Harding, M.
BirdLife International (2022) Species factsheet: Zosterops japonicus. Downloaded from http://www.birdlife.org on 16/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/08/2022.