• 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. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2022	Near Threatened	A2cd+3cd+4cd
2016	Least Concern
2012	Least Concern
2009	Least Concern
2008	Least Concern
2004	Least Concern
2000	Lower Risk/Least Concern
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	4,270,000 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	-	suspected	2016-2038
Rate of change over the past 10 years/3 generations (longer of the two periods)	20-29%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	20-29%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	20-29%	-	-	-
Generation length	7.31 years	-	-	-

Population justification: The global population of this species remains un-estimated. In oil palm plantations it appears to be too rare to generate reliable population densities (see Yahya et al. 2020) while in primary forest it has been recorded at densities of c.1.16 birds/km² in southern Thailand (Kempt et al. 2009). The species is often described as common or uncommon (del Hoyo et al. 1999, Wells 1999, Eaton et al. 2021) and appears relatively adaptable to habitat modification, occurring too in isolated park fragments in cities (eBird 2021).

Trend justification: Using a previous three-generation length period (27.9 years), and based on forest loss between 2000 and 2012, Tracewski et al. (2016) estimated this species to have lost 26% of its habitat. Although the three-generation period is now shorter (22 years; Bird et al. 2020), the rate of forest loss in the range of this species has accelerated since 2012, such that forest cover (with a canopy cover greater than 30%) is estimated to have been reduced by 24-28% over the last three generations (based on data between 2000 and 2020) (Global Forest Watch [2021], using Hansen et al. [2013] and methods disclosed therein). Much of this forest cover loss has been the result of complete clearance and conversion to oil palm plantations. Although this species does occur in oil palm (e.g. Yahya et al. 2020), it does so at lower densities than in primary forest (see Kemp et al. 2009 vs Yahya et al. 2020). It does, however, appear tolerant of fragmentation and can persists in heavily degraded areas, including urban parks (eBird 2021). For these reasons, population reductions are suspected to be at a lower rate than that of forest loss: suspected here to be 15-20%. This species is also affected by capture for the pet trade (Nijman & Nekaris 2017, Siriwat et al. 2020). Using assigned probability curves according to expert opinion on trade desirability in conjunction with accessibility to determine likely rates of population loss over the next three generations (they used a previous value of 34.8 years), Symes et al. (2018) estimated loss from hunting amounted to 16.5%, but this analysis had no term to account for reproduction and the species remains comparatively rare in market surveys in most of its range (Nijman & Nekaris 2017) with no indication the species is getting more desirable. Adjusting this rate for the current three-generation period and acknowledging that the species still appears rare in markets, hunting is suspected to be causing declines of 5-10%. Accumulating threats, the species is suspected to have declined 20-29% over the past three generations; this rate of decline is suspected to continue at the same rate into the future.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Brunei	extant	native	yes
Indonesia	extant	native	yes
Malaysia	extant	native	yes
Myanmar	extant	native	yes
Singapore	extinct	native	yes
Thailand	extant	native	yes

Country/Territory	IBA Name
Malaysia	Bako-Buntal Bay
Malaysia	Bau Limestone
Malaysia	Belum-Temenggor
Malaysia	Bintang Range
Malaysia	Central Titiwangsa Range
Malaysia	Danum Valley Conservation Area
Malaysia	Endau-Rompin
Malaysia	Gunung Pueh
Malaysia	Kabili-Sepilok
Malaysia	Kelabit Highlands
Malaysia	Klias peninsula
Malaysia	Krau Wildlife Reserve
Malaysia	Lambir Hills National Park
Malaysia	Lanjak Entimau Wildlife Sanctuary
Malaysia	Niah National Park
Malaysia	Panti forest
Malaysia	Pondok Tanjung Forest Reserve
Malaysia	Similajau National Park
Malaysia	South-east Pahang peat swamp forest
Malaysia	Tabin Wildlife Reserve
Malaysia	Taman Negara National Park
Malaysia	Tanjung Datu-Samunsam Protected Area
Malaysia	Tawau Hills Park
Thailand	Bala Sector, Hala-Bala Wildlife Sanctuary
Thailand	Khao Nor Chuchi

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	suitable	resident
Artificial/Terrestrial	Rural Gardens	suitable	resident
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Artificial/Terrestrial	Urban Areas	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	suitable	resident
Altitude	0 - 1600 m	Occasional altitudinal limits	(max) 2000 m

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Shifting agriculture	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%)		Rapid Declines		Medium Impact: 7
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Small-holder 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		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Species mortality

Purpose	Scale
Food - human	subsistence, national, international
Pets/display animals, horticulture	national, international

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Recommended citation
BirdLife International (2024) Species factsheet: Barred Eagle-owl Bubo sumatranus. Downloaded from https://datazone.birdlife.org/species/factsheet/barred-eagle-owl-bubo-sumatranus on 23/12/2024.
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 23/12/2024.