LC
Japanese Bush-warbler Horornis diphone



Taxonomy

Taxonomic note
Horornis diphone (del Hoyo and Collar 2016) was previously listed as Cettia diphone.

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
- - -

Red List history
Year Category Criteria
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

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

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 3,220,000 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals unknown not applicable not applicable 0
Population trend Stable 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 - - -
Largest subpopulations - - -
Generation length (yrs) 3.7 - - -

Population justification: The global population size has not been quantified, but in its non-breeding range, the species is described as uncommon to locally fairly common. Race restricta is now considered to be extinct. The introduced populations on Hawaii are now considered to be common to abundant on Oahu and spreading to other islands (del Hoyo et al. 2006). National population estimates include: c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in China; < c.50 individuals on migration and < c.50 wintering individuals in Taiwan; c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Korea; c.10,000-100,000 breeding pairs in Japan and c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Russia (Brazil 2009).

Trend justification: The population is suspected to be stable in the absence of evidence for any declines or substantial threats.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
China (mainland) N Extant
Japan N Extant
North Korea N Extant
Philippines N Extant
Russia N Extant
Russia (Asian) N Extant
South Korea N Extant
Taiwan, China N Extant
USA I Extant

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Japan Mount Hyonosen
Japan Mounts Nogo-hakusan and Ibuki

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

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - Non-trivial Recent

Recommended citation
BirdLife International (2019) Species factsheet: Horornis diphone. Downloaded from http://www.birdlife.org on 10/12/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 10/12/2019.