VU
Sao Tome Oriole Oriolus crassirostris



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(ii)

Red List history
Year Category Criteria
2018 Vulnerable C2a(ii)
2016 Vulnerable D1
2012 Vulnerable D1
2008 Vulnerable D1
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Average mass 50 g
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 640 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 2500-9999 poor estimated 2018
Population trend Decreasing poor inferred -
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 1 - - -
Largest subpopulations 100 - - -
Generation length (yrs) 3.7 - - -

Population justification: The population size had been previously thought to be very small. However, population density estimates (e.g. per Walther and Jones 2018) suggest that previous estimates may have been an underestimate. Based on such density estimates the population size is tentatively placed in the range 2,500-9,999 mature individuals.

Trend justification: The population is tentatively considered to be in decline as a result of ongoing habitat degradation.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
São Tomé e Príncipe N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
São Tomé e Príncipe São Tomé lowland forests
São Tomé e Príncipe São Tomé montane and cloud-forests
São Tomé e Príncipe São Tomé northern savannas
São Tomé e Príncipe Parque Natural Obô de São Tomé e Zona Tampão

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations marginal resident
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Moist Montane suitable resident
Savanna Dry marginal resident
Altitude 0 - 1600 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Scale Unknown/Unrecorded Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) No decline Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming 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: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation
Residential & commercial development Commercial & industrial areas Timing Scope Severity Impact
Future Minority (<50%) No decline No/Negligible Impact: 2
Stresses
Ecosystem degradation, Ecosystem conversion
Transportation & service corridors Roads & railroads Timing Scope Severity Impact
Ongoing Minority (<50%) No decline Low Impact: 4
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2020) Species factsheet: Oriolus crassirostris. Downloaded from http://www.birdlife.org on 15/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/08/2020.