Justification of Red List Category
This species has been uplisted to Endangered owed to a very rapid population reduction as a result of trapping for the cagebird trade, further compounded by forest loss and degradation across the species's range. Trends in forest loss and trapping levels need monitoring, and its tolerance of degraded forest should be determined.
The species is described as locally fairly common in the Lesser Sundas and Borneo, rare in Thailand and the Philippines and local and scarce in Peninsular Malaysia (del Hoyo et al. 2005). In Thailand, the species has been observed at 3-4 singers within an area of 3-4 hectares, albeit the species may have occurred at particularly high densities during surveys (Collar 2020), overestimating its true occurrence. Thus, due to high uncertainty, the global population size has not yet been quantified.
Based on a recent analyses by Symes et al. (2018), the species was considered to be undergoing a decline of 67.5% over a 10-year period, as estimated using data gathered between 2000-2015. Declines were attributed to the combined effect of habitat loss and trapping pressures (Symes et al. 2018, [also Tracewski et al. 2016]). This roughly equates to 78.1% decline over three generations (13.5 years; Bird et al. 2020). It is however important to note that surveys used to derive such trends were only conducted across the Greater Sundaic range, excluding quantification of any trends in the Lesser Sunda's and as such, potentially masking the true rate of decline over the species's overall range (F. Rheindt in litt. 2020). However, due to its known rarity, it is likely that the species has continued to decline at rate of at least 50%, with potential to exceed 70% over a three-generation period (as per Symes et al. 2018). Thus, the population here is suspected to be declining at a very rapid rate of 50-79%.
Geokichla interpres is found discontinuously from southern peninsular Thailand and Malaysia, through Borneo (including Brunei Darussalam), Sumatra and Java, to Lombok, Sumbawa and Flores, in Indonesia. It may also be a rare resident on several of the south-west Sulu Islands and Basilan in the central-southern Philippines. The species has recently colonised Krakatau island (Collar 2020). It is described as "generally rare and scarce" (Clement and Hathway 2000) throughout, and there are very few records from Sumatra and Kalimantan in particular, although it is probably under-recorded to some extent. It is considered fairly common in Borneo (Collar 2020). In Thailand, records are additionally scarce; two birds were found at Krung Ching Khao Luang National Park in 2005, a pair was found at Taleban National Park in 2018, and only one recent record was observed at a rubber plantation in the Satun province (I. Sa-ar in litt. 2020). It was formerly not uncommon in the Lesser Sundas and in Sabah (Malaysia), but is thought to have undergone a very rapid decline in recent years owing to logging and trapping for the cage bird trade.
It inhabits lowland primary deciduous and evergreen forest, often with a dense understorey, but has also been found in partially secondary forests, degraded forest, forest fragments, woodlands, and woodlots, although may fare poorly in heavily degraded areas (Clement and Hathway 2000, Collar 2020, D. Edwards in litt. 2020). Usually forages for invertebrates on the ground, but occasionally seen in fruiting trees (Clement and Hathway 2000). Breeding takes place from April or May to about late July or August, but probably with regional variation (Clement and Hathway 2000). Nest with 2-3 eggs placed up to 4 m above the ground (Clement and Hathway 2000).
Significant habitat loss is ongoing throughout the lowland forest range of this species, and studies from Sabah indicate that it occurs at a much lower density in logged forest (D. Edwards in litt. 2007, 2020). Owed to a number of factors such as land conversion for industrial plantations (such as for palm oil; L. Y. Ding in litt. 2020), and forest fires, the Sundaic lowlands had additionally experienced a loss of over 70% of its original forest cover by 2010 alone (Symes et al. 2018). In recent years it has also been very heavily exploited for the cage-bird trade across most of its range, particularly raising fears of its extirpation from some islands in Nusa Tenggara (Clement and Hathway 2000).
Conservation Actions Underway
The species occurs within a number of protected areas.
Medium small, sexes alike. Top of head and nape chestnut; back, rump, tail, wings, throat and breast black; tail tipped white; wing with white shoulder, white underwing coverts and white base to flight feathers form two stripes in underwing visible in flight. Lores, broken eyering and cheeks white, chin and throat with white streaks; lower breast and flanks white with black spots; belly and under tail coverts white. Bill black; eye dark brown, skin around eye dark grey; legs yellow. Similar spp. Ashy Thrush Z. cinerea, which is larger, lacks a chestnut crown and nape and has a more prominent white throat. Voice. A melodious set of two to four grating notes choo-ee-chew, choo-ee-chu-choo, dree-di-chu-choo or drrri-drii-dri, rising on the first two notes then falling; each set repeated every six to ten seconds.
Text account compilers
Butchart, S., Ding, L., Edwards, D., Hogberg, S., Hornbuckle, J., Khwaja, N., Mahood, S., Pilgrim, J. & Sa-ar, I.
BirdLife International (2023) Species factsheet: Geokichla interpres. Downloaded from http://www.birdlife.org on 26/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 26/03/2023.