Justification of Red List Category
This newly-split species is extremely poorly-known and has not been recorded with certainty since 1937, and is assumed to have a very small population (perhaps fewer than 2,500 mature individuals, given the paucity of records) which is inferred to be in decline owing to habitat loss and degradation in some areas, with all subpopulations likely to number fewer than 1,000 mature individuals. It has therefore been classified as Vulnerable, but better information is urgently needed.
There are no population data for this poorly-known species, but a preliminary estimate is that there may be fewer than 2,500 mature individuals, placed here in the band 1,000-2,500 mature individuals.
There are no data on population trends; however, logging and perhaps also hunting are suspected to be causing a decline in this species.
Rhizothera dulitensis has a very restricted range, being confined to Mt Dulit and Mt Batu Song, Sarawak, and Mt. Kinabalu, Sabah (19th C specimens), Malaysia (BirdLife International 2001, Davison 2008) and the range appears to be disjunct (Madge and McGowan 2002, Mann 2008, Myers 2009). No population estimates are available, but it is thought to be declining rapidly owing to habitat loss and degradation. There have been no records of this species since 1937 (Orenstein et al. 2010), but habitat within its elevational range is poorly-surveyed and rarely visited by birdwatchers (D. L. Yong in litt. 2013). There are records from the second half of the 20th century of a Rhizothera species near Tenom in the Crocker Range, Sabah, the identity of which has been regarded as having ‘not been determined precisely’ (Smythies 1999), although they appear to be attributed to R. longirostris by Davison (2008) and regarded as sight records of R. dulitensis by Phillipps and Phillipps (2011).
It is a highland bird of primary forest on limestone hills (BirdLife International 2001) from c.900-1,200 m (Smythies 1999).
Forest destruction in the Sundaic lowlands of Indonesia and Malaysia has been extensive because of a variety of factors, including the escalation of logging and land conversion, with deliberate targeting of all remaining stands of valuable timber including those inside protected areas, plus forest fires, and declines may be compounded by hunting and trapping for the cage-bird industry (BirdLife International 2001).
Conservation and research actions underway
There are historical records from Kinabalu National Park.
c. 37 cm. Long, fairly stout decurved bill, rufous face, broad grey band on throat and upper breast and clean white belly, upperparts brownish. Similar spp. Long-billed Partridge R. longirostris is similar but with rufous belly and greyish-rufous flanks, as well as whitish spots in the wing.
Text account compilers
Taylor, J., Martin, R, Benstead, P., Mahood, S., Symes, A. & Ashpole, J
Mahood, S. & Yong, D.
BirdLife International (2023) Species factsheet: Rhizothera dulitensis. Downloaded from http://www.birdlife.org on 30/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/03/2023.