VU
Ijima's Leaf-warbler Phylloscopus ijimae



Taxonomy

Taxonomic note

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.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - C2a(ii)

Red List history
Year Category Criteria
2016 Vulnerable C2a(ii)
2012 Vulnerable C2a(ii)
2008 Vulnerable C1; C2a(ii)
2007 Vulnerable
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Medium
Land mass type Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 133,000 medium
Extent of Occurrence non-breeding (km2) 2,260,000 medium
Number of locations 11-100 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 2500-9999 poor estimated 2000
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) 10-19 - - -
Decline (10 years/3 generation past and future) 10-19 - - -
Number of subpopulations 1 - - -
Largest subpopulations 100 - - -
Generation length (yrs) 3.6 - - -

Population justification: The global population is estimated to number a few thousand based on an analysis by BirdLife International (2001). It is estimated to number 2,500-9,999 mature individuals, equating to 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals. National population sizes have been estimated at c.50 individuals on migration and c.50 wintering individuals in Taiwan, and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Japan.

Trend justification: A moderate and on-going population decline is suspected owing to habitat change within the breeding grounds, as well as the low number of recent records.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Japan N Extant Yes
Philippines N Extant Yes
Taiwan, China N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Japan Oshima island
Japan Toshima island
Japan Niijima and Shikinejima Islands
Japan Kozushima island
Japan Miyakejima island
Japan Mikurajima island
Japan Hachijojima island
Japan Aogashima island
Japan Tokara islands
Philippines Mariveles mountains

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Dry major non-breeding
Forest Subtropical/Tropical Dry major breeding
Forest Subtropical/Tropical Moist Lowland major non-breeding
Forest Subtropical/Tropical Moist Lowland major breeding
Shrubland Subtropical/Tropical Moist suitable breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Wood & pulp plantations - Agro-industry plantations Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Pollution Agricultural & forestry effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Future Minority (<50%) Slow, Significant Declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion
Residential & commercial development Tourism & recreation areas Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Transportation & service corridors Roads & railroads Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2020) Species factsheet: Phylloscopus ijimae. Downloaded from http://www.birdlife.org on 13/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 13/07/2020.