Data Zone
Justification of Red List category
Although this species is widespread, it is scarce throughout its range and is suspected to be declining moderately rapidly owing to habitat loss. Its occurrence on slopes and occasionally degraded forest types, however, may mean it is less threatened than other lowland Sundaic species. Accordingly, it is listed as Near Threatened.
Population justification
The global population size has not been quantified but is believed to be large given the range and frequency of records across its range (eBird 2022). It is generally scarce within this range, occurring at low densities even in ideal habitat. However, mist-net studies on Borneo suggest that it is commoner than observational records suggest (del Hoyo et al. 2007). The exact habitat requirements of this species are not precisely known, with it being absent from many places it might be expected. Nonetheless, within its range, the rate of forest conversion to plantations, primarily oil palm, has been very rapid over the past few decades (per Global Forest Watch 2022) and this is thought to have had a significant impact on its population size. There are recent records from remaining forested areas across much of the range, however the extent of suitable habitat is now considerably smaller than three generations ago. Where habitat is secure the species continues to be regularly observed (eBird 2022), though observing the species away from protected areas is becoming increasingly difficult. In Thailand, there are recent records only from the Hala Bala Wildlife Sanctuary area and the population there must now be relatively small. Almost all records in Peninsular Malaysia now come from protected areas or forest concessions, while in Sumatra it is thought to have always been, and remains, scarce (van Marle and Voous 1988, eBird 2022). The largest area of suitable habitat undoubtedly lies on Borneo where the species is regularly observed in protected areas in Sabah. In Kalimantan, there are very few records (Mann 2008, eBird 2022) despite extensive forest. Nonetheless, this region is now likely to host a significant portion of the world population. Overall therefore, the population size is assumed still to be relatively large.
Trend justification
Stachyris leucotis is thought to be declining moderately rapidly in response to extensive forest cover loss across its range. Determining the rate of population decline for this species is difficult because of uncertainties surrounding its exact habitat requirements. In the absence of any other data, forest cover loss is used as a proxy for population reduction. In the three generations (10.8 years; Bird et al. 2020) to 2021, forest cover in this species' range was reduced by 16–18%, depending on the forest cover thresholds set (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). This value does not account for the impact of forest degradation, hence the population rate of reduction from habitat loss is likely to be greater than this. Similarly, since the species is most regularly encountered in low-lying forest (eBird 2022), where losses are greater, the overall rate of population reduction is suspected to be equivalent to c.16-25% over the last three generations. This rate is also precautionarily projected over the next three generations, although beyond that rates of loss may slow as the percentage area of forest outside protected areas diminishes.
Stachyris leucotis occurs in the Sundaic lowlands, from peninsular Thailand, Sabah, Sarawak and Peninsular Malaysia, Kalimantan and Sumatra, Indonesia and Brunei.
This species is found in primary evergreen forest, including logged forests and edge, from lowlands up to 1,000 m.
Forest destruction in the Sundaic lowlands of Indonesia and Malaysia has been extensive, for timber and conversion to agriculture. In particular the rapid expansion of oil palm has driven the conversion of the majority of remaining lowland forest in the region. Between 2010 and 2021, tree cover was reduced in its range by 16–18% (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). Most of this loss has occurred within the lowlands, where the highest densities of the species would be expected. Moreover, the impact of forest degradation will have added to rates of decline. Associated with the forest loss has been an increase in fire frequency, extent and severity, particularly during strong El Nino events (as in 1998). While the species can use secondary growth and higher elevations, the extent of the threats is such that this species' population is likely to be declining rapidly.
Conservation Actions Underway
None is known, however this species occurs in a number of protected areas throughout its range (UNEP-WCMC and IUCN 2022).
Conservation Actions Proposed
Conduct repeated surveys within the range to determine current distribution and abundance, as well as assess population trends and rates of habitat loss. Conduct ecological studies to improve understanding of its precise habitat requirements, particularly tolerance of secondary habitats and response to fragmentation. Effectively protect significant areas of suitable forest at key sites, in both strictly protected areas and community led multiple use areas.
Text account compilers
Berryman, A.
Contributors
Taylor, J., Gilroy, J. & Benstead, P.
Recommended citation
BirdLife International (2024) Species factsheet: White-necked Babbler Stachyris leucotis. Downloaded from
https://datazone.birdlife.org/species/factsheet/white-necked-babbler-stachyris-leucotis on 22/11/2024.
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 22/11/2024.