• 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
C2a(i,ii)	C2a(i,ii); D	B1ab(v); C2a(i,ii); D1

Red List history

Year	Category	Criteria
2018	Critically Endangered	C2a(i,ii)
2016	Critically Endangered	C2a(i,ii)
2015	Critically Endangered	C2a(i,ii)
2012	Critically Endangered	C2a(i,ii)
2009	Critically Endangered	C2a(i)
2008	Critically Endangered
2005	Critically Endangered
2004	Endangered
2000	Endangered
1996	Critically Endangered
1994	Critically Endangered
1988	Threatened

Migratory status	not a migrant	Forest dependency	high
Land-mass type	shelf island	Average mass	46 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	8,900 km2	medium
Severely fragmented?	yes	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	50-249 mature individuals	poor	estimated	2003
Population trend	decreasing	poor	suspected	-
Generation length	3.7 years	-	-	-
Number of subpopulations	2-100	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The currently known populations in the municipalities of San Mariano, Isabela and Baggao, Cagayan have been carefully monitored since 2012. The current population estimate in these two municipalities is 50 mature individuals. The total global population is precautionarily estimated to number fewer than 250 mature individuals, and so it is placed in the band 50-249 mature individuals. This equates to 75-374 individuals in total, rounded here to 70-400 individuals.

Trend justification: The species is suspected to be declining at an unquantified rate owing to the extensive loss of forest habitat on Luzon.

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

Country/Territory	IBA Name
Philippines	Mariveles mountains
Philippines	North Eastern Cagayan Protected Landscape and Seascape
Philippines	Northern Sierra Madre Natural Park
Philippines	Peñablanca Protected Landscape and Seascape

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	50 - 440 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 - Shifting agriculture	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		Majority (50-90%)		Rapid Declines		Medium Impact: 7
		Stresses Ecosystem degradation
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
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Oriolus albiloris	Timing		Scope		Severity		Impact
		Ongoing		Unknown		Unknown		Unknown
		Stresses Competition

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Recommended citation
BirdLife International (2024) Species factsheet: Isabela Oriole Oriolus isabellae. Downloaded from https://datazone.birdlife.org/species/factsheet/isabela-oriole-oriolus-isabellae 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.