Tanimbar Oriole (Oriolus decipiens) | Details

Tanimbar Oriole Oriolus decipiens

Current view: Data table and detailed info

Taxonomy

Taxonomic note
Oriolus bouroensis and O. decipiens (del Hoyo and Collar 2016) were previously lumped as O. bouroensis following Sibley and Monroe (1990, 1993).

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.

IUCN Red List criteria met and history

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2023	Least Concern
2016	Least Concern
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Species attributes

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

Range

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	8,100 km²
Area of Occupancy (breeding/resident)	4,600 km²
Severely fragmented?	no	-

Population

	Estimate	Data quality	Derivation	Year of estimate
Population size	75000-150000 mature individuals	poor	estimated	2022
Population trend	stable	-	suspected	-
Generation length	3.5 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: The global population size has not previously been quantified, but the species is described as moderately common (Coates and Bishop 1997; Eaton et al. 2016, 2021). Within this species' range, c.2,700 km² of forest remains (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). This species was formerly considered conspecific with O. bouroensis of Buru, which has been recorded at densities of c.92-193 individuals/km² (Poulsen 1998); applying this density to the present species, and assuming approximately 50% of forest is occupied, the population is estimated at c.125,000-250,000 individuals, or 83,000-166,000 mature individuals, rounded here to 75,000-150,000.

Trend justification: Data on population trends are lacking. Remote sensing data (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein) indicate that in the three generations to 2022, forest cover in the species' range reduced by 3-5%. However, it is described as very common 'even in heavily degraded [forest], forest edge habitat' and is reportedly one of the most regularly encountered Tanimbar endemics (J. Eaton in litt. 2023), thus habitat losses on this scale are not thought to be causing population declines. In the absence of other threats, the trend is suspected to be stable.

Country/territory distribution

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

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Mangrove Vegetation Above High Tide Level	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 320 m	Occasional altitudinal limits

Recommended citation
BirdLife International (2024) Species factsheet: Tanimbar Oriole Oriolus decipiens. Downloaded from https://datazone.birdlife.org/species/factsheet/tanimbar-oriole-oriolus-decipiens on 19/12/2024.
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 19/12/2024.