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

Taxonomic source(s)
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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2023	Least Concern
2016	Near Threatened	A2c+3c+4c
2012	Near Threatened	A2c+3c+4c
2008	Near Threatened	A2c; A3c; A4c
2004	Near Threatened
2000	Lower Risk/Near Threatened
1994	Lower Risk/Near Threatened
1988	Lower Risk/Least Concern

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	350,000 km2	medium
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)	1-9%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Generation length	3.55 years	-	-	-
Number of subpopulations	2-4	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The population size of this species has not been quantified, although it is described as fairly common (B. Harris in litt. 2016, Eaton et al. 2021). The total area of suitable habitat, spanning more than 40,000 km², is large, and eBird (2022) data suggest the species does not occur at a particularly low density. Consequently, the population size is likely to be much larger than 10,000 mature individuals.

Trend justification: The population is suspected to be declining slowly due to habitat loss at the lower elevations of its range. In the three generations (10.7 years; Bird et al. 2020) to 2022, forest cover loss in its range was 2-4% (Global Forest Watch 2022, based on Hansen et al. [2013] and methods disclosed therein), and this is thought to have had an equivalent (hence minimal) impact on the population. Trapping for the songbird trade has also been identified as a threat to this species. However, the species has only very rarely (and in small numbers) appeared on physical market survey inventories (Chng et al. 2016, 2018), and using a web-scraping tool to mine data from online marketplace platforms, Okarda et al. (2022) found no D. sumatranus among c.105,000 listings, although they did detected 162 "Dicrurus sp.", at least some of which may refer to this species. Consequently, although trapping may cause local losses at the most accessible locations, it is unlikely to be causing significant reductions in global population size. Evaluating all the data available, the population is suspected of declining at a past and future rate of 1-9% over three generations. With much of the range lying in protected areas, there is little prospect of the rate of declining substantially worsening in the near-future.

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

Country/Territory	IBA Name
Indonesia	Bukit Bahar - Tajau Pecah
Indonesia	Bukit Barisan Selatan
Indonesia	Bukit Kaba
Indonesia	Gunung Dempo
Indonesia	Gunung Leuser
Indonesia	Kerinci Seblat
Indonesia	Meranti
Indonesia	Pulau Siberut
Indonesia	Siak Kecil

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	suitable	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	0 - 1600 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		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Agro-industry plantations	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Scale
Pets/display animals, horticulture	national

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Recommended citation
BirdLife International (2024) Species factsheet: Sumatran Drongo Dicrurus sumatranus. Downloaded from https://datazone.birdlife.org/species/factsheet/sumatran-drongo-dicrurus-sumatranus on 23/11/2024.
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 23/11/2024.