NT
Orange-necked Partridge Arborophila davidi



Justification

Justification of Red List Category
This partridge is listed as Near Threatened because, despite its small population and very small range, it occurs at many sites and the largest subpopulation is believed to be close to 1,000 mature individuals. While deforestation in the region is suspected to be causing a population decline, the rate of this decline is not currently thought to be sufficently rapid to approach the thresholds for listing as Vulnerable owing to the reported tolerance that this species and congeners show to a degree of forest degradation.

Population justification
The species is now known from many sites in southern Viet Nam and one site in Cambodia. The area of suitable habitat has been found to be more extensive than was previously thought, and given the population densities recorded in several congeners and their ability to persist in partly degraded habitats it seems likely that the population approaches 10,000 individuals, which equates to 6,667 mature individuals and it is thus placed in the band 2,500-9,999 mature individuals. The majority of the population occurs in southern Viet Nam, but the largest subpopulation is suspected to be close to as few as 1,000 mature individuals, depending on population connectivity in a region with highly discontinuous remaining suitable habitat.

Trend justification
This species is assumed to have declined owing to forest clearance and hunting within its small range, but it is probably tolerant to some degree of forest degradation. An analysis of deforestation from 2000 to 2012 found that forest within the species's range was lost at a rate equivalent to 18% over three generations (Tracewski et al. 2016). The population is therefore assumed to decline at a rate of 10-19% over three generations. Declines are thought to be continuing as forest clearance continues.

Distribution and population

Arborophila davidi is known from southern Viet Nam and eastern Cambodia. Recent surveys have expanded its known range in Viet Nam: it has now been recorded from Cat Tien National Park, Dong Nai Protected Forest Management Board (T. Evans in litt. 2007), Vinh An State Forest Enterprise (SFE), Nghia Trung SFE, Bu Gia Map NP, Bu Dop SFE, Vinh Cu Natural and Historical Reserve and Tan Phu SFE (Nguyen Tran Vy 2006), Da Teh SFE (Nguyen Xuan Dang et al. 2004), Binh Phouc SFE (Nguyen Xuan Dang and Osborn 2004) and Dak O SFE. It is predicted to occur in a number of other sites and may be widespread in southern Lam Dong, Dong Nai, Binh Duong and Binh Phuoc provinces, where suitable habitat remains. A single bird was camera-trapped in Seima Biodiversity Conservation Area (SBCA), Mondulkiri Province, Cambodia in 2002 (Davidson et al. 2002). The species has been recorded subsequently from the same very locality, but it remains enigmatic in the area, with an inexplicably patchy distribution (E. Pollard in litt. 2009). Based on current evidence, the area of suitable habitat in Cambodia may be as small as 70 km2 (E. Pollard in litt. 2009). The species is apparently rare (or perhaps just elusive) in some areas. A slow decline is suspected owing to on-going pressures placed on forest habitats, but the apparent ability of this species (as well as many congeners) to tolerate degraded habitats suggests that current forestry operations are unlikely to represent a major threat.

Ecology

It is resident in evergreen forest in lowlands and foothills, from 120 m to at least 600 m, particularly hills covered with non-thorny bamboo. It also thrives in a variety of secondary habitats including tall scrub, bamboo, Acacia, logged evergreen and semi-evergreen forest plantations, perhaps preferring bamboo-covered slopes with a thick leaf-litter layer. Thus it appears to be able to tolerate considerable habitat disturbance and modification. Pairs call in duet. Calling reportedly peaks in March, but has been recorded in November in Cambodia.

Threats

Extensive deforestation, particularly from herbicide spraying during the Viet Nam war, presumably triggered a historic decline. Habitat loss through commercial logging, unofficial timber collection and clearance of land for cultivation (including cashew nut, cassava, rubber and other crop plantations), compounded by high hunting levels across its restricted range, now represent the main threats. Until recently these factors operated in the Cat Loc and Cat Tien protected areas as a result of ineffective management and regulation enforcement, stemming from lack of resources and staff. Illegal forest clearance by settlers has been prevalent in Snoul Wildlife Sanctuary, Cambodia in recent years and 120 km2 of the protected area are in the process of being degazetted to allow further clearance. There is currently extensive legal collection of bamboo in the SBCA, although the impact of this on the species is unknown (Le Manh Hung et al. 2006).

Conservation actions

Conservation Actions Underway

In May 1998, a five-year project began in Cat Tien National Park and Cat Loc Nature Reserve (now administratively integrated), focusing on research, developing a conservation management plan, capacity building, community development and conservation education. The Orange-necked Partridge is one of the project's flagship species, and featured on a national stamp in 2000. Extensive surveys have also been carried out in Bu Gia Map National Park (S. Browne in litt. 2004). The known Cambodian population is within the SBCA, a former logging concession which is being managed to promote biodiversity conservation since 2002, primarily by controlling illegal hunting, encroachment and land conversion (Davidson et al. 2003, C. Samnang in litt. 2004, Le Manh Hung et al. 2006). Snuol Wildlife Sanctuary presumably also holds a population, but receives limited protection, with no external support to the Ministry of Environment (T. Evans in litt. 2007). Following surveys in Binh Phouc Province, Viet Nam, the ecological requirements of the species have been refined and recommendations made to extend the boundaries of Bu Gia Map National Park and to create a 'species habitat protection area' for the benefit of Orange-necked Partridge and Germain's Peacock-pheasant Polyplectron germaini within Nghia Trung and Bu Dang State Forest Enterprises (Le Manh Hung et al. 2006).

Conservation Actions Proposed

Identify and implement management requirements for the species within protected areas in Cambodia and Viet Nam. Initiate a conservation education programme for the local people who live around selected protected areas. Quantitatively monitor the populations in Cat Tien and Cat Loc. Conduct surveys for further populations in the largest patches of suitable habitat, such as those in southern Lam Dong, Dong Nai and Binh Duong provinces. Conserve any further sites found to support populations, and follow recommendations to extend the boundaries of Bu Gia Map NP. Continue conservation management improvements in Cat Tien National Park. Carry out ecological studies to determine seasonal habitat use and response to disturbance. Assess the threat posed by hunting to this species and determine what levels of hunting pressure it can withstand. Support the conservation management of SBCA and Snoul Wildlife Sanctuary, Cambodia and Cat Loc, Nam Cat Tien and Bu Gia Map in Viet Nam. Survey the Cambodian population to assess its size and global importance. Improve training and resources for forest rangers.

Identification

27 cm. Well-marked partridge with bold, black-and-white head markings and orange neck flush. Similar spp. Recalls Bar-backed Partridge A. brunneopectus, but differs primarily by broader black band through eye, black gorget, orange neck flush, broader supercilium behind eye, grey on underparts and larger black flank markings. Voice Territorial call, accelerating series of prruu notes, running into rapid series of up to 70 pwi notes. Also, very rapid tututututututututututu (up to 60 notes). Partner often accompanies with slower, stressed tchew-tchew-tchew-tchew. Weak, airy pher or phu notes when agitated.

Acknowledgements

Text account compilers
Taylor, J., Wheatley, H., Davidson, P., Harding, M., Benstead, P., Bird, J., Keane, A.

Contributors
Browne, S., Evans, T., Pollard, E., Samnang, C., Tordoff, J. & Tran Vy, N.


Recommended citation
BirdLife International (2022) Species factsheet: Arborophila davidi. Downloaded from http://www.birdlife.org on 17/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/08/2022.