CR
Rück's Blue-flycatcher Cyornis ruckii



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
D D D1

Red List history
Year Category Criteria
2021 Critically Endangered D
2016 Critically Endangered D
2013 Critically Endangered D
2012 Critically Endangered D
2010 Critically Endangered D1
2009 Critically Endangered D1
2008 Critically Endangered
2004 Critically Endangered
2000 Critically Endangered
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status unknown Forest dependency unknown
Land-mass type shelf island
Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 6,600 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 1-49 mature individuals poor estimated 2000
Population trend unknown - - -
Generation length 3.3 years - - -
Number of subpopulations 1 - - -
Percentage of mature individuals in largest subpopulation 100% - - -

Population justification: The population is assumed to be tiny (fewer than 50 individuals and mature individuals) based on a lack of records, despite searches, since two specimens were collected in 1917-1918.

Trend justification: Population trends are unknown and are thus not quantified.


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
Indonesia Gunung Leuser

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland possible resident
Altitude 150 - 200 m Occasional altitudinal limits (min) 0 m

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 Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Small-holder grazing, ranching or 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: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2024) Species factsheet: Cyornis ruckii. Downloaded from https://datazone.birdlife.org/species/factsheet/rucks-blue-flycatcher-cyornis-ruckii on 25/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 25/02/2024.