Current view: Data table and detailed info
Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions 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 |
continent
|
Average mass |
268 g |
Population justification: A previous population size (BirdLife International 2016) is considered to have been an underestimate. The species has been modelled as having an area of suitable habitat between 66,000 and 80,000 km2 (Bagaria et al. 2021), and where dedicated fieldwork has been carried out within this area the species is typically present (although unobtrusive). An investigation into the species in Thrumshingla National Park, Bhutan, provided density estimates of 1.67 (1.27-2.17) individuals per square kilometer based on calling birds (Dhendup 2015), equivalent to a population size of between 80,000-140,000 mature individuals. Consequently, it appears most plausible that the population currently exceeds thresholds for listing as threatened under the population size criterion.
However, this highly-forest dependent species (primarily responding to the presence of dense bamboo rather than canopy cover) has suffered from a low but continuing rate of forest cover loss from within its mapped range over the past three generations, and is known to additionally suffer from high hunting pressure in at least parts of the range such as the Mishmi Hills. In combination, these threats are suspected to be causing a decline in mature individuals, as the population size is considered to be directly related to habitat area and also to be reduced by hunting. But the impact of climate on the future extent of the species's habitat may cause an acceleration in the rate of population reduction: bioclimatic envelope modelling predicts that of current suitable habitat, 47% will become unsuitable by 2070 while only an additional 8% will become newly suitable (Bagaria et al. 2021). If these changes are already occurring, this would be the equivalent of a linear rate of loss of 21% over the next three generations, with any impacts from other threats additional to this.
Trend justification: The species is suspected to have been declining at a slow rate in the recent past, owing to on-going forest conversion driven by a slowly expanding human population within its range coupled with high hunting pressure in parts of the range. Significant measures have been taken to safeguard forests in Arunachal Pradesh and Bhutan, lending hope that suitable habitat can be conserved. However, the species is predicted to be one of the galliformes that is most severely impacted by climate change (Bagaria et al. 2021), which may see an acceleration of the rate of population reduction. Bioclimatic envelope modelling predicts that 47% of current suitable habitat will become unsuitable by 2070, offset by an increase of only 8% becoming newly suitable (Bagaria et al. 2021). Assuming a direct relationship between area of suitable habitat and population size, a net area change of -39% between 2021 and 2070 would be expected to result in a linear rate of population reduction equivalent to 21% over the three-generation period between 2021 and 2035, while an exponential rate of population reduction would be equivalent to 32% over the same period. The former is the more plausible shape of the projected reduction given the threat (which may manifest as an accelerating impact), hence the rate of reduction over the next three generations due to this threat is suspected not to exceed 21%. The uncertainty around this prediction may be large but is not quantified: the individual species model for the bioclimatic envelope modelling performed relatively poorly but the ensemble model (with several galliform species with similar habitat requirements included) performed well, but missed a significant extent of this particular species's postulated occurrence (supplementary information in Bagaria et al. 2021).
Forest loss due to conversion for agriculture is considered most likely to continue at a similar rate as most recently estimated: a maximum three-generation equivalent of 2.4% (data from Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). It is unclear how this loss will interact with changes predicted due to a shifted climatic envelope. The impact of hunting on the species may be significant in small pockets of the range: in the Mishmi Hills hunting pressure has been reported to be severe but there are large parts of the range that are largely undisturbed, as well as a significant proportion of the range being within protected areas. The impact of hunting is therefore unlikely to have a significant impact on the total population.
Overall, past rates of population reduction are suspected to have been in the range 1-9% over three generations, while the predictions from the bioclimatic envelope model suggest that a best value for a future reduction is 21%, although within a wide band, here given as 10-29%. A rate of reduction that includes the present will be fastest for the period which extends furthest into the future, between 2020 and 2034, and is placed in the band 10-25%, but is still predicted to be just above 20% over this period.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Chestnut-breasted Partridge Arborophila mandellii. Downloaded from
https://datazone.birdlife.org/species/factsheet/chestnut-breasted-partridge-arborophila-mandellii 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.
