Data Zone
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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to 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
Exact population size estimates for this species are not available, however it is described as common in most of the range. Indeed, it is the most common bird in secondary forest on Hong Kong and also the most popular cage-bird in China (van Balen 2019a). It is abundant on Taiwan. The subspecies Z. s. williamsoni is considered common around the Gulf of Thailand and Z. s. erwini is common in peninsular Malaysia, but scarce in Malaysian Borneo and Brunei. On Sumatra the species was common, but there are concerns that the very high numbers of individuals trapped may be impacting the population. Subspecies Z. s. salvadorii is abundant on Enggano (Eaton et al. 2016).
Trend justification
An overall slow decline may be inferred due to the high levels of trapping.
Swinhoe's White-eye is abundant on Taiwan. The subspecies Z. s. williamsoni is considered common around the Gulf of Thailand and Z. s. erwini is common in peninsular Malaysia, but scarce in Malaysian Borneo and Brunei. On Sumatra, Indonesia, the species was common, but there are concerns that the very high numbers of individuals trapped may be impacting the population. Subspecies Z. s. salvadorii is abundant in wooded areas on Enggano Island, Indonesia (Eaton et al. 2016). The subspecies Z. s. hainanus is present on Hainan island, China (van Balen 2019a.).
There are five subspecies within Swinhoe's White-eye (Zosterops simplex). These are: simplex, hainanus, erwini, williamsoni and salvadorii.
Z. s simplex and Z. s. hainanus occupy deciduous or mixed forests, thickets, open woodland, secondary growth, as well as cultivated areas (e.g. urban parks, gardens, farmlands, groves, orchards). In winter, they may occupy tall forest trees. They breed mainly in lowlands. They occur up to 800 m in southern China and up to 2,590 m in south-east Asia in non-breeding areas (van Balen 2019a). Z. s erwini and Z. s. williamsoni occupy deciduous, broadleaf evergreen/semi-evergreen and swamp-forest, as well as forest edge, secondary growth, woodland, farmland, thickets, all zones of mangroves (mature and regenerating), scrub and wooded cultivation (orchards, parks, gardens, cardamon plantations). They can also be found in open strand woodland, especially with stands of casuarinas, and coastal scrub of all kinds. They generally occur between 200–1600 m, but also locally in true lowlands. In Borneo, Z. s. erwinii is restricted to mangroves, swamp-forest and non-forest (edges of wet rice fields and scrub along riverbanks), mainly adjoining coastal areas. Along Gulf of Thailand coast, Z. s. williamsoni is confined to belt of mangroves and scrub (van Balen 2019b). Z. s. salvadorii inhabits coconut groves and other lowland wooded areas on Enggano Island (van Balen 2019c).
Despite very high levels of trapping in some parts of the species’s range, it remains abundant in many places.
Text account compilers
Elliott, N., Butchart, S., Ekstrom, J., Harding, M.
Recommended citation
BirdLife International (2024) Species factsheet: Swinhoe's White-eye Zosterops simplex. Downloaded from
https://datazone.birdlife.org/species/factsheet/swinhoes-white-eye-zosterops-simplex on 19/12/2024.
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 19/12/2024.