||Garrulax bicolor Hartlaub, 1844
||Sumatran Laughingthrush, Black-and-white Laughingthrush
||del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
||30 cm. Brownish-black with unmistakeable white head with slightly erectile crest extending to the breast, distinctive triangular black forehead, lores and drooping eye-stripe. Similar spp body colour of bicolor is darker than continental forms of White-crested Laughingthrush Garrulax leucolophus, lacking the rufous or mouse-brown tones shown in that species.
|Red List Category & Criteria:
||Butchart, S. & Symes, A.
||Brickle, N., Hogberg, S., Shepherd, C., Owen, A., Eaton, J. & Chng, S.
||Bird, J., Butchart, S., Gilroy, J., Taylor, J., Allinson, T & Martin, R
The species has suffered a very rapid, ongoing population decline due to trapping for trade compounded by habitat loss. Local extinctions have been observed across much of the range within the past 10-15 years concurrent with price increases and reduced availability in the market. For these reasons Black-and-white Laughingthrush is evaluated as Endangered.
|Previously published Red List assessments:|
- 2013 – Vulnerable (VU)
- 2012 – Vulnerable (VU)
- 2008 – Vulnerable (VU)
- 2007 – Vulnerable (VU)
- 2004 – Not Recognized (NR)
- 2000 – Not Recognized (NR)
- 1994 – Not Recognized (NR)
- 1988 – Not Recognized (NR)
|Range Description:||Garrulax bicolor was originally distributed along the length of the montane spine of Sumatra, Indonesia, from Aceh in the north to Lampung in the south (van Marle and Voous 1988), and was reportedly common. Recent evidence suggests that it has undergone a very considerable decline and become locally extinct at several locations where it present less than a decade ago (Eaton et al. 2015). It was present at a small number of sites scattered across Sumatra, including Bukit Barisan Selantan National Park, Danau Ranau (South Sumatra) (R. Thomas per C. R. Shepherd in litt. 2012), Batang Toru (North Sumatra) and Ulu Masen (Aceh) (N. Brickle in litt. 2007), and a single locality in Kerinci Seblat National Park (S. Högberg in litt. 2006). However, since 2012 there have been few records away from Aceh province. A small group of three birds was camera trapped in Batang Toru (G. Fredriksson per C. R. Shepherd in litt. 2012).|
|♦ Continuing decline in area of occupancy (AOO):||Yes|
|♦ Extreme fluctuations in area of occupancy (AOO):||No||♦ Estimated extent of occurrence (EOO) - km2:||218000|
|♦ Continuing decline in extent of occurrence (EOO):||Unknown||♦ Extreme fluctuations in extent of occurrence (EOO):||No|
|♦ Continuing decline in number of locations:||Yes|
|♦ Extreme fluctuations in the number of locations:||No||♦ Lower elevation limit (metres):||750|
|♦ Upper elevation limit (metres):||2000|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The species was reportedly common and widespread in 1988 but is now known few sites throughout the range where only very small numbers have been located in the wild recently. More than 45 km of transects in suitable habitat in 2013 returned only a single record of the species (Eaton et al. 2015). Trappers in West Sumatra stated in 2015 that it remained in forests three days walk from a road (Eaton et al. 2015). The largest extent of remaining habitat is in Aceh province, where the species is still relatively widespread though highly localised and heavily trapped (Eaton et al. 2015). Recent bird tours to this area have located groups by the roadside, indicating that trapping pressure is lower in this culturally separate region of Sumatra (Eaton 2014). The paucity of records from the majority of the range indicates that the species now has a small population size.|
For these reasons it is believed to have a small population and is placed in the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.
Trend Justification: Numbers in trade have been falling coincident with a rapid increase in the price per bird from $8-15 in 2007 to $90 in 2014 (Chng et al. 2014, Harris et al. 2015), and this data is coupled with an expert review of the status of the bird in the wild concluding that it was 'Severely Declining' (Harris et al. 2015). In the wild the species appears to have disappeared from several sites where it was being regularly recorded only a decade ago.
|Current Population Trend:||Decreasing|
|♦ Number of mature individuals:||2500-9999||♦ Continuing decline of mature individuals:||Yes|
|♦ Extreme fluctuations:||No||♦ Population severely fragmented:||No|
|♦ No. of subpopulations:||2-100||♦ Continuing decline in subpopulations:||Unknown|
|♦ Extreme fluctuations in subpopulations:||No||♦ All individuals in one subpopulation:||No|
|♦ No. of individuals in largest subpopulation:||1-89|