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.
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 |
shelf island
|
Average mass |
- |
Population justification: The population size of this species has historically thought to have been small, although there is little evidence to support this. Singh et al. (2021) predicted that the area of suitable habitat for this species (in 2010) was c.45,000 km2. Even allowing for a substantial contraction in the area since then (thought to have been 20-35%), the area of habitat available to this species remains large: c.30,000-36,000 km2. On Palawan, one of the species' two congenerics, P. falcata, has been recorded at densities of 4.8 and 11.2 individuals/km2 in advanced secondary growth and old growth respectively (Mallari et al. 2011). Although the suitability of these figures for P. leucogrammica is ultimately unknown, eBird (2022) suggest the two species' have similar detectability. If the true density of P. leucogrammica lies somewhere between 5-10 individuals/km2, and the calculation made by Singh et al. (2021) is correct, the species likely still numbers in the hundreds of thousands, set here to 75,000-150,000 assuming approximately 50% occupancy.
Trend justification: Using a Maxent approach derived from climate and land-use layers with GBIF (2019) data, Singh et al. (2021) predicted that the area of suitable habitat for this species will fall by 66–71% between 2010 and 2050, equivalent to declines of 25–26% over three generations (10.5 years) if a linear decline is assumed. This rate of reduction is also supported by historic and future projections of remote-sensed forest cover data (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein), which suggest forest cover reduced by 23-25% in the three generations to 2021, with similar projected losses into the future based on data from between 2018 and 2021. Given this species' high forest dependence, these are considered the minimum rates of population loss. There is concern, however, that these reductions in habitat area do not necessarily fully account for threats in this species' decline. It appears to be intolerant of even moderate habitat degradation (Lambert 1992) such that selective logging is thought to impact it, as is the increasing fragmentation of suitable forest patches (Collar and Robson 2020). Overall therefore, it is plausible that population reductions exceed 30%, and this is accepted here with a likely rate of decline of 25-35% over three generations.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Bornean Wren-babbler Ptilocichla leucogrammica. Downloaded from
https://datazone.birdlife.org/species/factsheet/bornean-wren-babbler-ptilocichla-leucogrammica on 23/12/2024.
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 23/12/2024.
