Data Zone
Justification of Red List category
Previously the species was not considered to be threatened, as it was observed to be common across a wide range including several strictly protected areas. The range remains relatively large; however, while the species has some tolerance of forest degradation, it is still dependent on flat, lowland forest below 500 m. An estimated 20% of tree cover has been lost from the area suitable for the species since 2001, largely through conversion of lowland forest to agricultural plantations. These now cover nearly half of the potential range of the species. As such the species is suspected to have undergone a moderately rapid to rapid population reduction of between 20 and 30% over the past three generations. The rate of forest loss may slow in the future, simply because such a large proportion of the available land has already been cleared.
Population justification
The global population size has not been quantified. The current extent of potentially suitable habitat is approximately 29,000 km2, though this includes a large extent of habitat close to the upper limit of the elevation utilised by the species, where densities may be low. A further 25,000 km2 within this elevation range has already been converted to plantations (Harris et al. 2018). In the remaining habitat that is suitable, the species is still commonly encountered, and is tolerant of logging and is recorded in secondary forest (D. L. Yong in litt. 2021), suggesting that the overall population size remains large. However, the population is suspected to be undergoing a moderately rapid to rapid population decline from the rate of tree cover loss within the range of this forest-dependent species, which exceeds 20% and may approach 30% over the past three generations (Global Forest Watch 2021).
Trend justification
Within the range of the species habitat conversion, primarily for oil palm, has proceeded exceptionally rapidly in the past two decades. Verma et al. (2020) found that of the species they studied across Sundaland, this one had the greatest increase in the the proportion of the range impacted by human activity over the period 2000-2015. While the range of the species is more extensive than the distribution extent that was considered for that study, the growth of human footprint on the species has certainly been swift. Absolute tree cover loss within the suitable elevational range has been 26.3% over the 14 years (three generations) from 2006 to 2020, when using the forest cover estimate for 2000 corrected for loss prior to 2006 as a baseline (Global Forest Watch 2021). Using the forest cover estimate for 2010, the total loss to 2020 has been 16.1%, equivalent to a loss of 20.9% of tree cover within the suitable elevational range of the species over three generations (Global Forest Watch 2021).
Tropicoperdix graydoni occupies a wide area of Sabah (Borneo), Malaysia (BirdLife International 2001; GBIF.org 2021a,b). The species is common in Danum Valley (BirdLife International 2001) and survives in logged forest (Myers 2009; Phillipps and Phillipps 2011), but requires flat, plains-level forest which has been very rapidly cleared for the planting of plantations, especially oil palm. The extent of suitable elevation is approximately 54,000 km2, of which 25,100 km2 had been converted to plantations by 2015 (Harris et al. 2018). Much of this conversion has taken place in the past two decades, and has also partly fragmented the much diminished range of the species.
This species inhabits lowland forest to 500 m, though is likely to be most abundant at plains level and seems to avoid hilly areas, even where these are within the elevational range (J. A. Eaton in litt. 2021). There are records up to 800 m (GBIF.org 2021a,b), however it is likely that the location information for these records is imprecise. It is common in primary forest, but also occurs in secondary and logged forest (D. L. Yong in litt. 2021).
The main threats are the conversion and degradation of lowland, flat forest to agricultural plantations. The species is able to persist in logged forest, and occurs in secondary forest, but its habitat requirements overlap with the most productive land for the growth of agricultural commodities, and absolute tree cover loss (overwhelmingly the conversion of primary forest to plantations) stands at 32% between 2001 and 2020 within its range. Primarily this has been for the production of oil palm.
While the species may be trapped occasionally, this is not considered likely to have significant population impacts (Symes et al. 2018).
Conservation actions in place
No specific actions known, though it was included in the Status, Survey and Conservation Action Plan (McGowan et al. 1995). It occurs in several protected areas.
Conservation actions needed
Protect large areas of flat, plains-level forest. Establish a monitoring program for Sabah, using a network of sample sites that are repeatedly visited using a simple methodology in order to establish presence/absence across the region at a reasonable scale and to allow the inference of abundance change.
26-32 cm. Medium sized forest partridge with chestnut collar and dirty-white ear-patch, lacks a clearly defined black necklace from lower throat to ear coverts. Similar spp. A. tonkinensis has narrower chestnut collar and smaller, pale chestnut ear-patch. From Bar-backed Partridge A. brunneopectus by plainer upperside, heavy black breast markings, reddish bill with greenish tip, greenish to yellowish-green legs and distinctive ear-patch and collar. From extralimital Scaly-breasted and Annam Partridges A. merlini by ear-patch and collar. Voice Similar to Scaly-breasted (see Annam).
Text account compilers
Martin, R.
Contributors
Benstead, P., Eaton, J., Mahood, S., Taylor, J. & Yong, D.
Recommended citation
BirdLife International (2024) Species factsheet: Sabah Partridge Tropicoperdix graydoni. Downloaded from
https://datazone.birdlife.org/species/factsheet/sabah-partridge-tropicoperdix-graydoni on 27/12/2024.
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 27/12/2024.