Data Zone
Justification of Red List category
This species has a large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The species is suspected to be declining but does not meet or approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is unknown and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size has not been quantified, but the species is described as uncommon and scarce everywhere within its range (del Hoyo et al. 2005, Eaton et al. 2021). It was previously split from Bornean Whistling-thrush M. borneensis and Javan Whistling-thrush M. glaucinus, formerly all lumped under Sunda Whistling-thrush M. glaucinus. The two other species are both widespread, however M. castaneus is scarce on Sumatra, apparently occupying a narrower niche, possibly owing to competition with Shiny Whistling-thrush M. melanurus (Collar 2004).
Trend justification
As a forest-dependent species it is suspected to be declining owing to habitat loss and degradation. Deforestation is widespread and continuing on Sumatra, now extending deep into this species’ elevational range. Forest cover extent in this species' range reduced by c.8% overall in the three generations to 2022 (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein). The species may be affected by trapping to some extent, though this is unconfirmed. Tentatively, declines are placed in the range 5-15% in three generations and this is suspected to continue.
Myophonus castaneus is endemic to the island of Sumatra in Indonesia where it occurs in the foothills and mountains.
The species is found in hill and mountain forest between 400 and 1,600 m (van Marle and Voous 1988, Eaton et al. 2021). It occurs in the subcanopy and middle-storey along watercourses and dry riverbeds (Collar 2005).
Deforestation is the principal threat to this species. At least a third of montane rainforest on Sumatra has already been lost, primarily as a result of agricultural encroachment and logging. These factors are affecting large areas of lower montane rainforest, even within protected areas.
Conservation Actions Underway
The species occurs in a number of protected areas but law enforcement within these is often poor.
c.25 cm. Male has metallic blue forehead, bluish-black upper body shading on upper back, scapulars and belly to chestnut lower body, tail and wings. Bill and legs blackish. Female and immature are almost entirely chestnut, with brownish-grey head. Immatures can have a bluish sheen on upper nape. Similar spp. Differs from other whistling-thrushes in its chestnut plumage.
Text account compilers
Vine, J.
Recommended citation
BirdLife International (2024) Species factsheet: Sumatran Whistling-thrush Myophonus castaneus. Downloaded from
https://datazone.birdlife.org/species/factsheet/sumatran-whistling-thrush-myophonus-castaneus on 26/12/2024.
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 26/12/2024.