• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species is restricted to a narrow elevational range and has a very small to small population of between 900 and 3,000 mature individuals. However, almost the entire range is well-protected and largely inaccessible, and there are not believed to be significant threats to the species at present. As such, the species is assessed as Near Threatened.

Population justification
The population size has been reported as c. 200-2,000 individuals, with reported density of 8 birds/km² in 125-250 km² of habitat (McGowan & Kirwan 2020). Davison & Scriven (1987) reported densities of 1.9 males/km² on Gunung Rabong and 2.7-3.0 males per km² on Gunung Tahan, and that the total number of males on Gunung Rabong in May 1976 was only 15 (BirdLife International 2001). The confirmation of the species's occurrence in Terengganu (Liang et al. 2018) increases the total area within the suitable elevation (a maximum area of habitat) to 490 km². If all of this area were occupied at recorded densities of 3.8-6 mature individuals/km², i.e. using the above densities of calling males and assuming an equal sex ratio (a precautionary assumption), then the range of population size is 1,862-2,940 mature individuals. Should occupancy be lower, it is plausible that the lower bound of the population would fall below 1,000 mature individuals.
Given the uncertainty inherent in these calculations, the most precise estimate of population size for Malaysian Crested Argus is here considered to be 900-3,000 mature individuals, but it is most likely that the population is greater than 1,000 mature individuals.

Trend justification
There is no recent information about the population trend in Malaysia. The threats to the species are considered minimal given that almost the entire range lies within the well-protected Taman Negara National Park, however the population within the Dungun Timber Complex may be impacted by selective logging (Liang et al. 2018) and there is the possibility that illegally-set snares could capture the species, though it is not thought to be a target of hunters (Liang et al. 2018, Norsyamimi et al. 2020). In the absence of significant threats, the population is suspected to be stable.

Rheinardia nigrescens occurs only in a narrow altitudinal band in montane, tall dipterocarp forest on the eastern flanks of the East Coast Range of Peninsular Malaysia within, or very close to, Taman Negara National Park (Davison 1979, Mamat & Yasuk 1998, Wells 1999, Davison et al. 2020). Outside of the boundary of Taman Negara National Park there are records from Gunung Rabong in Kelantan (Mamat & Yasak 1998) and the Dungun Timber Complex in Terengganu (Liang et al. 2018).
The total mapped area within this elevation range is 492 km². Scaling this to a 2 km by 2 km grid gives a maximum Area of Occupancy value of 1,068 km². Any subpopulation structure is uncertain: it is likely that despite the apparent breaks in the areas of suitable elevation individuals do disperse between areas, hence it is more likely there is a single population (G. Davison in litt. 2021).

It inhabits tall hill dipterocarp/lower montane transitional forest on sandstone mountains (Davison & Scriven 1987), within the elevations of 680-1,400 m (Liang et al. 2018) but most records are from above 800 m and below 1,150 m (Mamat & Yasak 1998, Liang et al. 2018, McGowan & Kirwan 2020). Most of the range lies within Taman Negara National Park and almost all records are from tall, unlogged old-growth forests, suggesting that it is reliant on closed-canopy forest and is likely to be sensitive to any level of logging (Liang et al. 2018). There is one record in stunted, bamboo-dominated forest (of a single feather only) (Mamat & Yasak 1998). It is terrestrial, feeding predominately on vegetation, fruit and invertebrates but also sometimes amphibians (McGowan & Kirwan 2020). It is exceedingly wary (BirdLife International 2001).
It is speculated that the current distribution is as a result of exclusion from lowland areas by Great Argus Argusianus argus (Davison 1978, 1979, Davison & Scriven 1987, BirdLife International 2001, Liang et al. 2018). 

The majority of suitable habitat lies within Taman Negara National Park, and as such the species is largely protected from significant threats (Liang et al. 2018). The main documented threat is low levels of selective logging leading to habitat degradation in the periphery of Taman Negara National Park and in the Dungun Timber Complex (Liang et al. 2018, McGowan & Kirwan 2020). There is concern that logging operations will move into the elevation range of the species as valuable timber is depleted in the lowlands (Liang et al. 2018). Should this happen, the risk posed by trapping will also increase as access is improved to these remote areas: snares (set for large mammals) have been recorded during surveys for the species and incidental capture is possible (Liang et al. 2018).

Conservation Actions Underway
CITES Appendix I. It occurs in Taman Negara National Park in Malaysia. Treated with R. ocellata within the Status survey and Action Plan for Pheasants 2000-2004 (Fuller and Garson 2000), but this is outdated.

Conservation Actions Proposed
Protection of the old-growth montane forests in the Dungun Timber Complex will be important to the conservation of the Crested Argus, alongside management measures to ensure strong connectivity of the forests in this landscape with Taman Negara, to the north-west, under the Central Forest Spine Master Plan for Ecological Linkages (DTCPPM 2009). Forest cover within the mapped range should be monitored on an ongoing basis. Additionally, enforcement operations by the relevant to tackle poaching will have to be strengthened to conserve large-bodied birds and mammals (Liang et al. 2018). 

Male 190-239 cm, female 74-75 cm. Large pheasant with enormous tail. Male blackish-brown, peppered whitish all over. Buff supercilium and throat and drooping, blackish-brown and white crest. Female is smaller, shorter-tailed and warm brown with blackish and buff bars, speckles and vermiculations. Somewhat paler below. Voice At dancing grounds, very loud woo'o-wao. Also series of far-carrying oowaaaa phrases.

Text account compilers
Martin, R.

Contributors
Brickle, N., Wells, D.R., Yong, D., Davidson, G. & Benstead, P.

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Recommended citation
BirdLife International (2024) Species factsheet: Malaysian Crested Argus Rheinardia nigrescens. Downloaded from https://datazone.birdlife.org/species/factsheet/malaysian-crested-argus-rheinardia-nigrescens 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.