CR
Isabela Oriole Oriolus isabellae



Taxonomy

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
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
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Land-mass type - shelf island
Average mass 46 g
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 8,900 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 50-249 poor estimated 2003
Population trend Decreasing poor suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations 2-100 - - -
Largest subpopulations 1-89 - - -
Generation length (yrs) 3.7 - - -

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 distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Philippines N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Philippines Mariveles mountains
Philippines North Eastern Cagayan Protected Landscape and Seascape
Philippines Peñablanca Protected Landscape and Seascape
Philippines Northern Sierra Madre Natural Park
Philippines Quirino Protected Landscape

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Altitude 50 - 440 m Occasional altitudinal limits  

Threats & impact
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

Recommended citation
BirdLife International (2020) Species factsheet: Oriolus isabellae. Downloaded from http://www.birdlife.org on 21/09/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/09/2020.