Data Zone
Justification of Red List category
Pellorneum buettikoferi is listed as Near Threatened due to a suspected c.25% population reduction over the past three generations (11 years). There is high uncertainty over this reduction as very little is known about the species tolerance for degraded habitats, as well as its population size and distribution.
Population justification
There are very few records of Pellorneum buettikoferi across its range (Verbelen 2009). The species is more commonly observed in national parks on the south of the island, and to the north of the island (eBird 2024), but this in large part reflects survey effort. The species may widespread across Sumatra, but little is known about its conservation status and it is likely often overlooked due to its skulking behaviour and nondescript plumage (Verbelen 2009).
As there is scarce information on the distribution and habitat requirements of the species, and no comprehensive surveys that allow a density estimation, it is not possible to estimate the population size.
Trend justification
Poorly known but suspected to be declining in response to widespread forest loss on Sumatra. Over the past three generations, forest cover loss within this species' range was 24.4% (Global Forest Watch 2024, based on data from Hansen et al. [2013] and methods disclosed therein), a value very similar to the 26.6% reduction calculated by Symes et al. (2018). Because this species is considered highly forest-dependent, this rate of reduction is considered broadly representative of population trends. However, there are uncertainties over the species’ distribution, with its known range only covering a small portion of the island. There is also little known about the species’ habitat preferences, and it appears to have some tolerance for degraded woodlands (Verbelen 2009). The forest loss data may therefore underestimate the reduction if its habitat is being disproportionately impacted, but could also overestimate it if forest loss disproportionately impacts areas that do not host the species. A range of 10-40% is provided to account for these uncertainties. A best-estimate of 25% is provided in line with the calculated forest loss data.
Pellorneum buettikoferi is endemic to Sumatra, Indonesia, where it has been described as uncommon (van Marle and Voous 1988). However, the species may be widespread across Sumatra, but little is known about its conservation status and it is probably often overlooked due to its skulking behaviour and nondescript plumage (Verbelen 2009). The species has a known presence in edge habitats in Gunung Leuser National Park in the north and Bukit Barisan National Park in the south where it was observed in small groups of two to five birds (Verbelen 2009, Gooddie 2015).
P. buettikoferi is endemic to Sumatra, occurring up to 1,100 m (Eaton et al. 2021) in primary forest, swampy forest, and logged/cleared evergreen forest (Collar and Robson 2020, Haryoko 2020, Eaton et al. 2021). The species skulks in undergrowth at edges and scrubs (Verbelen 2009, Eaton et al. 2021), foraging on the ground for insects (Collar and Robson 2020). The species can occupy open clearings, even in agricultural landscapes, provided there is sufficient understory cover (Verbelen 2009, Eaton et al. 2021).
The loss and degradation of forest is the most likely threat impacting this species. Widespread conversion of lowland forests to plantations has been ongoing on Sumatra since the 1980s (Haryoko et al. 2020, Collar and Robson 2020).
Conservation Actions Underway
This species is present in Gunung Leuser, Bukit Tigapuluh, Way Kambas and Bukit Barisan national parks (Verbelen 2009, Gooddie 2015).
15 cm. A nondescript babbler with disproportionately short tail, pale grey face. Crown, upperparts and side of neck olive-brown, tinged dull grey on crown and nape, with slight rufous tinge on upperwing and tail, pale feather shafts on crown forming narrow but fairly conspicuous streaking; lores, eyering and cheek pale buff with some olive-grey mottling or fine scaling, not sharply set-off from ear-coverts and stripe above eye, which are olive-grey with narrow pale shaft streaks; underparts, including underwing-coverts, isabelline-buff, grading to pale cream or off-white on throat and on mid-belly, and into darker greyish-ochre on lower flanks and on outer thigh; upper breast marked with faint grey triangular marks; iris pale amber or red to pale brown; upper mandible grey, cutting edges and lower mandible horn-flesh; legs pale horn-flesh, sometimes pale yellow. Differs from very similar T. tickelli in paler plumage, shorter tail. Sexes similar. Juvenile is close to adult in colour, differing mainly in looser-webbed plumage, especially on belly to undertail-coverts; grey marks on breast vestigial or absent, lower flanks and undertail-coverts paler greyish-isabelline, mid-belly purer and more extensively white. Sounds: Song a rather loud “pwiyu pii biyo” and “pii byo pwiyu”, resembling that of Trichastoma rostratum but repeated more quickly and consisting of 3 whistles.
Text account compilers
Richardson, L.
Contributors
Wells, D.R., Benstead, P., Khwaja, N., Symes, A. & Gilroy, J.
Recommended citation
BirdLife International (2024) Species factsheet: Sumatran Babbler Pellorneum buettikoferi. Downloaded from
https://datazone.birdlife.org/species/factsheet/sumatran-babbler-pellorneum-buettikoferi on 24/11/2024.
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 24/11/2024.