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

Taxonomic note
Oriolus xanthonotus and O. consobrinus were previously lumped as O. xanthonotus (del Hoyo and Collar 2016) but were split based on based on phylogenomic, bioacoustic, biometric and morphological analyses (Rheindt et al. 2022). Two subspecies recognized.

Taxonomic source(s)
Handbook of the Birds of the World and BirdLife International. 2023. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 8. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v8_Dec23.zip.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

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

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	300,000 km2	good
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	medium	inferred	2016-2027
Rate of change over the past 10 years/3 generations (longer of the two periods)	10-20%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	10-20%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	10-20%	-	-	-
Generation length	3.6 years	-	-	-
Number of subpopulations	2-50	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: Fundamentally unknown. Qualitative descriptions of abundance on Borneo range from 'common and widespread' (Mann 2008) to 'uncommon' (Eaton et al. 2021), but these interpretations include also Bornean populations of O. xanthonotus (the two having only recently been separated as distinct species: Rheindt et al. 2022). On Palawan, described as 'fairly common' (Allen 2020). Citizen science data suggest that on both islands it is relatively common in lowland forest blocks (eBird 2023); while it appears able to persist in mature Acacia mangium and Albizia plantations, albeit at lower densities than in forest (Styring et al. 2011), there is no evidence that it can persist in even mature oil palm plantations (Koh and Wilkove 2008, Styring et al. 2011). While the population is not thought to be small (there remains a large amount of suitable habitat), it is thought to have considerably decreased over the past 20-30 years in response to large-scale conversion of land to oil palm plantations.

Trend justification: Undoubtedly declining in response to conversion of forest habitats to plantations, although this species is tolerant of some degradation, and declines are not thought to have exceeded 20% over the past three generations, and are unlikely to accelerate in the near future. According to remote sensing data, forest cover loss in this species range over the past three generations was equivalent to 14-19%, depending on the assumptions used (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein). This species is considered moderately forest-dependent, with most records from lowland forest, where it evidently occurs at the highest densities (Styring et al. 2011, eBird 2023). While the species occurs in Acacia mangium and Albizia plantations (Styring et al. 2011), a large proportion of land conversion in its range has been conversion to oil palm plantations, which this species does not occur in (Koh and Wilkove 2008, Styring et al. 2011). While the remote sensing data used here is insensitive to forest degradation, this is not thought to be a key threat to this species, which regularly occurs in forest edge and mature second growth. Consequently, over the past three generations (10.8 years: 2012-2023) O. consobrinus is suspected to have declined by 10-20%. This same rate is precautionarily assumed to occur over the next three generations, although thereafter rates of reduction may begin to slow, as an increasing percentage of this species' range will lie in protected areas.

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

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	marginal	resident
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	marginal	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	suitable	resident
Altitude	0 - 500 m	Occasional altitudinal limits	(max) 1200 m

Threat (level 1)	Threat (level 2)	Impact and Stresses
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	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

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Recommended citation
BirdLife International (2024) Species factsheet: Ventriloquial Oriole Oriolus consobrinus. Downloaded from https://datazone.birdlife.org/species/factsheet/ventriloquial-oriole-oriolus-consobrinus on 26/12/2024.
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 26/12/2024.