• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic note
Previously placed in Trichastoma (del Hoyo and Collar 2016) but moved to this genus following Cai et al. (2019). Previously treated as conspecific with P. tickelli; precise relationships to congeners require elucidation. Monotypic.

Taxonomic source(s)
Handbook of the Birds of the World and BirdLife International. 2021. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 6. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v6_Dec21.zip.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A2c+3c+4c

Red List history

Year	Category	Criteria
2024	Near Threatened	A2c+3c+4c
2016	Near Threatened	A2c+3c+4c
2013	Near Threatened	A2c+3c+4c
2012	Near Threatened	A2c+3c+4c
2008	Near Threatened	A2c; A3c; A4c
2005	Near Threatened
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	-

	Estimate	Data quality
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	poor	suspected	2016-2027
Rate of change over the past 10 years/3 generations (longer of the two periods)	10-40,25%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	10-40,25%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	10-40,25%	-	-	-
Generation length	3.61 years	-	-	-

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.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Indonesia	extant	native	yes

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	suitable	resident
Forest	Subtropical/Tropical Swamp	suitable	resident
Shrubland	Subtropical/Tropical Moist	suitable	resident
Altitude	0 - 1100 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation

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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.