Data Zone
Justification of Red List category
This species has a fairly 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 suspected to be in slow decline but 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 generally described as common (Collar and Robson 2021). In bird surveys of the wet and montane zone of Sri Lanka 2007-2009, Goodale et al. (2014) had 1,989 detections of this species and Kotagama and Goodale (2004) recorded it as being the most abundant species in mixed-species flocks.
Trend justification
The population is precautionarily suspected to be in slow decline, but may be stable. Some populations are precautionarily suspected to be declining because of habitat degradation (the species is absent from small plots of degraded wet zone forest near Horana and Galle [E. Goodale in litt. 2020]), although remote sensing data suggest that recent forest loss in this species' range is minimal (Global Forest Watch [2021], using data from Hansen et al. [2013] and methods disclosed therein), equivalent to 2-3% over the past three generations. Moreover, the species seems more abundant in secondary forest (logged in the 1970s and 1980s) than in primary forest (E. Goodale in litt. 2020).
Turdoides rufescens is endemic to Sri Lanka, where it is fairly common to common in the wet lowlands, and usually rare on adjacent hills but is occasionally common above 1,000 m.
This species is abundant in primary and secondary forest in the wet zone of Sri Lanka (Goodale et al. 2014). It also occurs in degraded forest, scrub and tea plantations, and even visits villages in close proximity to forest. The species is well-known as the gregarious leading species of mixed-species flocks in lowland Sri Lanka (Kotagama and Goodale 2004); in mixed-species flocks it averages 15 individuals (but up to 45) per flock. It is more spottily distributed in the montane zone, where it is quite rare, but has been recorded in the Horton Plains (elevation 2,180 m) (E. Goodale in litt. 2020).
Forest on Sri Lanka has suffered degradation and fragmentation in recent decades due to excessive gathering of fuelwood, clearance for permanent agriculture, shifting cultivation, fire, urbanisation and logging.
Conservation Actions Underway
Occurs in numerous protected areas.
Conservation Actions Proposed
Monitor populations and habitat trends across the range. Conduct ecological studies to determine precise habitat requirements and response to fragmentation. Protect significant areas of forest at key sites, in both strictly protected areas and community-led multiple use areas.
Text account compilers
Taylor, J., Berryman, A., Mahood, S.
Contributors
Goodale, E.
Recommended citation
BirdLife International (2024) Species factsheet: Orange-billed Babbler Argya rufescens. Downloaded from
https://datazone.birdlife.org/species/factsheet/orange-billed-babbler-argya-rufescens on 25/11/2024.
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 25/11/2024.