Data Zone
Justification of Red List category
This Vietnamese endemic is listed as Endangered because it has a very small range on the Da Lat Plateau, within which it is at high risk from the threat of trapping, which has caused catastrophic regional declines in other laughingthrush species. It probably also has a small population size (<10,000 mature individuals).
Population justification
The population size of this species has not been directly estimated. Robson (2008) and Craik and Lê (2018) both describe it as locally common, corroborating the report of Mahood and Eames (2012) that it is a 'common [species] wherever suitable habitat is found'; the latter authors also found it at 93% (13 of 14) of survey locations where broadleaf evergreen forest was found at a suitable elevation. According to Global Forest Watch (2024) data, approximately 640 km2 of forest lies within its elevational range, although a portion of this is pine forest (which does not host it). Densities for congeners are also unavailable, however it is precautionarily assumed to have a moderately small population comprising 2,000–10,000 mature individuals, but this requires corroboration.
Trend justification
The two principal threats to this species are habitat loss and degradation, and trapping. In the three generations (10.9 years; Bird et al. 2020) to 2023, only c.1% of forest cover was lost in its range (Global Forest Watch 2024, based on data from Hansen et al. [2013] and methods disclosed therein) and some of this may refer to landslides. While this does not include habitat degradation, this too has been minimal (Grantham et al. 2020). Consequently, forest loss and modifications are not thought to be causing declines. Trapping is now thought to comprise a more substantial threat and is known to have removed birds from previously occupied sites (J. Eaton in litt. 2023), as well as having caused the rapid declines in several other laughingthrushes on the Da Lat Plateau, namely Orange-breasted Laughingthrush Garrulax annamensis and White-cheeked Laughingthrush Pterorhinus vassali. Given the pressure on this species, and localised evidence of disappearances, trapping is inferred to be causing declines. However, it remains commonly encountered at some sites, including those easily accessible to hunters, and some parts of its albeit small range are remote and comparatively difficult to access; consequently, declines are not thought to be rapid. Future trends are impossible to predict however, with G. annamensis declining precipitously and somewhat unexpectedly in the last five years because of trapping. The present species' small ranger renders it particularly vulnerable to market whims and changes in demand, and so this should be closely monitored.
Trochalopteron yersini is endemic to the Da Lat plateau, Viet Nam (Mahood and Eames 2012).
It is resident in dense undergrowth of primary and logged montane evergreen forest, secondary growth and scrub bordering forest, occupying a narrow altitudinal band from 1,500–2,440 m, although it has been recorded below 1,450 m (Mahood and Eames 2012). It is generally encountered in monospecific flocks of 4–8 individuals. Juveniles have been collected between April–June, suggesting the main breeding season is probably from March-May.
A government resettlement programme has greatly increased human pressure on the Da Lat Plateau. While concern in response to this was previously directed about putative accelerations in forest loss, degradation and fragmentation, these have so far failed to materialise, with much of this species' range remaining unmodified (Global Forest Watch 2024). By far the most impactful threat, which has insidiously increased in acuity and extent over the past two decades, is that of trapping to fuel Viet Nam's songbird trade. The scale and extent to which this poses an extinction risk to this species is not well understood, but there is evidence of other laughingthrushes being heavily trapped in and around Da Lat, and this species has disappeared from sites it once occupied. Given its relatively small range, not much of this species' habitat can be considered wholly secure from trapping.
Conservation Actions Underway
Part of its range is protected (e.g. Bi Doup Nui Ba National Park) but the extent to which this status buffers T. yersini from trapping pressure is unknown.
26-28 cm. Striking, black-hooded, orange-brown laughingthrush with silver ear-patch. Blackish primary coverts contrast with bright golden to orange-olive wing-feather fringes. Voice Song is repeated, loud, rising wueeeeoo, u-weeeeoo, uuuu-weeoo or wiu-weeeu, often answered with low, mewing wiaaah, ayaaa or ohaaaah. Subdued, harsh, slurred grreet-grreet-grreet-grreet-grreet-grreet-grrr-rr when alarmed.
Text account compilers
Berryman, A.
Contributors
Mahood, S., Hung, L., Benstead, P., Westrip, J.R.S. & Eaton, J.
Recommended citation
BirdLife International (2024) Species factsheet: Collared Laughingthrush Trochalopteron yersini. Downloaded from
https://datazone.birdlife.org/species/factsheet/collared-laughingthrush-trochalopteron-yersini on 21/12/2024.
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 21/12/2024.