Data Zone
Justification of Red List category
This forest-associated species is listed as Near Threatened because it is suspected to be undergoing a moderately rapid decline (20-29% over three generations) owing to the extensive loss of lowland forests from large areas of the Sundaic lowlands.
Population justification
The global population size of this species has not been quantified, but it is scarce throughout its range, although evidently unobtrusive (Wells 1999, Eaton et al. 2021, eBird 2024) in remaining tracts of lowland forest, which remain widespread, although much reduced in extent compared to three generations ago. Accordingly, its global population size is likely to be relatively large.
Trend justification
No direct population trend data are available for this species, however remote sensing data are considered a suitable proxy for this forest-dependent species. Over the past three generations, forest cover within its range reduced by c. 18-22% (Global Forest Watch [2024], based on data from Hansen et al. [2013] and methods therein). This species is commonest at lower elevations (below 600 m, despite occasionally reaching 1,200 m: Eaton et al. 2021), where rates have been most rapid, and the species may be additionally impacted by forest degradation and fragmentation. Accordingly, rates of population reduction may be slightly higher than remote sensing data alone indicate. Accordingly, the rate of population reduction for the past three generations is set at 20-29%.
Harpactes diardii occurs in the Sundaic lowlands, from peninsular Thailand, Sabah, Sarawak and Peninsular Malaysia, Kalimantan and Sumatra, Indonesia and Brunei (BirdLife International 2001). It formerly occurred in Singapore but is now considered extinct there, with no record since 1921.
This species occurs in the middle and lower storeys of primary and logged evergreen forests in lowlands and hills. It is mainly found below 600 m, although there are records up to 1,200 m (Eaton et al. 2021). It has also been recorded from peatswamp forest, luxuriant secondary forest and even cocoa plantations (in areas with adjacent forest cover).
The chief threat to this species is forest loss, which has been especially rapid in the Greater Sundaic bioregion due to timber extraction and the proliferation of plantations (chiefly oil-palm and rubber). These threats are thought to have driven declines of more than 20% over the past three generations. Forest fires associated with climate change may become more frequent over time, adding an additional pressure to this species including in protected areas. There is no evidence, however, that the species is heavily trapped.
Conservation Actions Underway
This species occurs in numerous protected areas across its range, which safeguard it from more precipitous rates of population decline. No specific measure is known.
Conservation Actions Proposed
Continue to monitor rates of population decline using habitat extent as a proxy. Protect more areas of lowland forest. Instigate longer-term monitoring at some sites to determine whether there are additional threats to habitat loss.
Text account compilers
Richardson, L., Berryman, A.
Recommended citation
BirdLife International (2024) Species factsheet: Diard's Trogon Harpactes diardii. Downloaded from
https://datazone.birdlife.org/species/factsheet/diards-trogon-harpactes-diardii on 23/12/2024.
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 23/12/2024.