Current view: Data table and detailed info
Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Zhou Fang; Jiang Aiwu. 2008. A new species of Babbler (Timaliidae: Stachyris) from the Sino-Vietnamese border region of China. The Auk 125(2): 420-424.
IUCN Red List criteria met and history
Red List criteria met
Red List history
| Migratory status |
not a migrant |
Forest dependency |
high |
| Land-mass type |
continent
|
Average mass |
- |
Population justification: The area from which this species has been proven to occur has grown considerably since its discovery (sensu Zhou and Jiang 2008). In the most detailed evaluation to date, Jiang et al. (2020) identified a realised/occupied area of habitat covering 555 km2, but with a much larger area (c. 4,500 km2) of total potentially suitable habitat, much of which remains to be surveyed; the authors acknowledged however that their course modelling approach may, in places, have exaggerated the area of suitable habitat, suggesting this should be treated as a maximum value. Nonetheless, initial field validations of their model in China suggest promising accuracy, and there is little doubt that this species occupies a (potentially much) greater area than previously supposed.
In China it is known from six places (Li et al. 2013, Yu et al. 2014, Jiang et al. 2020, eBird 2023): two areas of Nonggang National Nature Reserve (present only in Longhu and Nonggang sections; apparently absent from Longshan south of the Zuo River: Jiang et al. 2020); Chunxiu Nature Reserve; Qinglongshan Nature Reserve; Xialei Nature Reserve; and Bangliang Gibbon National Nature Reserve. Applying densities they obtained during surveys, Li et al. (2013) suggested the number of individuals may be >2,000 in Nonggang, Bangliang, Chunxiu and Trung Khanh (Vietnam [which was not surveyed as part of this study; see below]), although they do also suggest the global population may be as low as 1,500 individuals. Given the species has now been found at Qinglongshan Nature Reserve (Yu et al. 2014) and Xialei Nature Reserve (Jiang et al. 2020), these numbers now seem overly precautionary; in particular, the modelling exercise by Jiang et al. (2020) found that Xialei hosts more highly suitable habitat than anywhere else outside of Nonggang, and validated this with ground-truthing surveys, detecting 21 birds across four transects (of five) that were placed in habitat designated as highly suitable. It is therefore likely that Xialei hosts a population of several hundred birds.
In Vietnam, it is known only from the extreme north-east, in Cao Vit Gibbon Conservation Area (Eames and Truong 2016, eBird 2023), but modelling by Jiang et al. (2020) suggests a much larger area of potentially suitable habitat lies in the country. However, there are two reasons to caution against a confident assumption that Vietnam hosts a large population: (1) There remain no records in the country away from Cao Vit Gibbon Conservation Area, despite some survey effort in the areas they identify (eBird 2023), albeit not specifically for this species such that it may have been overlooked; and (2) The vast majority of karst in Vietnam is considered by Jiang et al. (2020) to be of medium/intermediate suitability (only 14.4% of highly suitable habitat is in Vietnam). In their own ground-truthing in China, areas of this suitability description predictably had comparatively low success in finding babblers; for example, three transects in 'medium suitable' habitat in Gulongshan Nature Reserve failed to find it at all. Even this, however, is not conclusive as the species evidently does not have very high detectability when not vocalising: e.g. Li et al. (2013) did not find the species at Qinglongshan, when Yu et al. (2014) did. Accordingly, much of the area in Vietnam is mapped in this assessment as 'possibly extant' rather than definitely so. Future surveys in Vietnam would be advised to target the area of karst immediately adjacent to Chunxiu Nature Reserve (China), which Jiang et al. (2020) identify as high suitability, and is an area large enough to potentially support multiple hundreds of birds.
Compiling the available data, the population is estimated to number at least 2,500 mature individuals (based on densities detected by Li et al. [2013] being applied to the area of known occupancy sensu Jiang et al. [2020]). This should however be seen as the minimum likely population, with some areas of apparently highly suitable habitat not yet surveyed for this species (Jiang et al. 2020). Nonetheless, the number is limited to a somewhat small area of available karst in this species' likely range; accordingly the maximum likely population size is estimated to be 5,000 mature individuals.
Trend justification: The population trend of this species has not been directly quantified. However, it is inferred to be declining due to ongoing forest disturbance and modification that is rendering habitat unsuitable. This species is a forest-specialist, confined to a small area of limestone karst in southernmost China and neighbouring Viet Nam where most available habitat is already mostly degraded. Its exact habitat requirements are inexactly known but the species is evidently dependent on the most intact forests, and is absent from the most degraded forests (apparently anything <40% forest cover), scrub and agricultural areas (Jiang et al. 2020, eBird 2023). In the past three generations (11 years: 2012–2023), forest cover in its range decreased by 3–4% (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein), mostly in the periphery of suitable habitat. This is thought to have caused slow declines over the past ten years and with only 30% of the species' suitable habitat circumscribed in a protected area, declines are likely to continue.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Nonggang Babbler Stachyris nonggangensis. Downloaded from
https://datazone.birdlife.org/species/factsheet/nonggang-babbler-stachyris-nonggangensis 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.
