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

Justification of Red List category
This species is confined to plains-level and lowland forests on Borneo and is suspected to be undergoing a rapid decline because of pervasive forest loss, driven principally by the conversion to plantations (especially palm oil). For this reason it is assessed as Vulnerable.

Population justification
The global population size has not been quantified. Although it is widespread across Borneo, it has very specific habitat requirements and is largely considered scarce to rare. For example, in Sungai Wain Protection Forest, east Kalimantan, it was encountered just 32 times in 44 months of survey effort (Fredriksson and Nijman 2004). Given its specific habitat requirements and apparent low density, generating an accurate population estimate for this species is a priority.

Trend justification
This lowland forest specialist is suspect to be declining rapidly because of pervasive forest loss within its range which largely has consisted of total clearance or conversion to oil palm plantations, neither of which this species persists in. Forest cover loss in its elevational and geographic range over the past three generations (18 years; Bird et al. 2020) has been approximately 36-40% (Global Forest Watch [2021] using data from Hansen et al. [2013] and methods disclosed therein), increasing fractionally to a rate of c.41% in the period 2016-2020. This latter rate is suspected to continue into the future with little sign of abatement. As a forest dependent species, this is the absolute minimum suspected population reduction. In addition, degradation and fragmentation is suspected to have driven further reduction, though this is unquantified. Consequently, the species is suspected to have declined, and to continue to decline, by 40-49% over three generations.

Carpococcyx radiceus, treated separately from the threatened Sumatran Ground-cuckoo C. viridis, is endemic to the island of Borneo (Brunei Darussalam, Sabah and Sarawak, Malaysia, and Kalimantan, Indonesia) (BirdLife International 2001). This cuckoo is widely regarded as scarce to very rare and is confined to primary forest and tall/mature secondary forest. It principally occurs below 500 m (Eaton et al. 2021) and appears to favour alluvial forest. 

This species is a plains-level and lowland forest specialist occurring in dense forest over dry ground in lowland dipterocarp forest, and undulating lowland and low hilly forest, with a preference for alluvial areas near rivers (Long and Collar 2002, Erritzøe et al. 2012, Eaton et al. 2021). It is shy and little known, foraging on the forest floor (on arthropods and fruit), and sometimes following army-ant swarms, bearded pigs Sus barbatus and sun bears Helarctos malayanus (Long and Collar 2002, Fischer et al. 2017).

Lowland forests in Borneo have been dramatically reduced in extent and quality by human activities such as logging and plantation agriculture (especially oil palm). Forest fires are also a more moderate threat. This species does occasionally get caught in snares, however if found alive is usually released owing to its bad taste (BirdLife International 2001) and so hunting is considered to be driving only negligible declines. This species appears to have an at least partially mutualistic relationship with Sus barbatus (Fischer et al. 2017), and so may be impacted by the heaving hunting pressures exerted on this species.

Conservation Actions Underway
The species occurs within a number of protected areas on Borneo and was studied within Sungai Wain protected Forest where patrol teams have controlled hunting pressure, stopped illegal logging and maintained fire breaks. Education work is carried out in the local community.

Conservation Actions Proposed
Expand conservation actions that have been introduced successfully at Sungai Wain Protected Forest to other forest areas. Combat forest fires in the future. Generate a density estimate for the species by surveying using playback, and estimate its global population size. Continue to monitor rates of habitat loss.

Text account compilers
Taylor, J., Symes, A., Berryman, A., Bird, J., Benstead, P.

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Recommended citation
BirdLife International (2024) Species factsheet: Bornean Ground-cuckoo Carpococcyx radiceus. Downloaded from https://datazone.birdlife.org/species/factsheet/bornean-ground-cuckoo-carpococcyx-radiceus on 23/11/2024.
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 23/11/2024.