Justification This warbler qualifies as Vulnerable because it has a small, declining and fragmented population as a result of habitat loss, potentially compounded by pesticide use and trapping during migration.

Family/Sub-family Sylviidae

Species name author (Stejneger, 1882)

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Identification 10-12 cm. Small, stocky, warbler. Bright olive-green above and white below. Long buffish-white supercilium, broad dark olive-brown eye-stripe and lores. Slightly mottled ear-coverts and cheeks. Single whitish wing-bar. Faint greyish wash to sides of breast and flanks. Yellowish undertail-coverts. Pale flesh legs. Similar spp. Arctic Warbler P. borealis is larger, stockier, has yellowish supercilium, cheeks and underparts. Voice Mechanical swee-seww-swee-swee-swee, usually ending in chew. Call a louder twee.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

2,500-9,999

decreasing

350 km²

Yes

Range & population Phylloscopus ijimae is endemic to Japan. It breeds on the Izu Islands, between Oshima and Aogashima, and was recently discovered nesting on Nakano-shima in the Tokara Islands. There are non-breeding/passage records from Honshu, Kyushu and the Nansei Shoto Islands, where it probably winters. It is also reportedly a regular migrant on the Osumi peninsula in Kagoshima ken¹. It may also winter in Taiwan (China) (two specimens collected) and the Philippines (one record [several specimens] from Luzon). It has declined markedly since the 1970s.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It occurs mainly in the canopy of deciduous, mixed and evergreen subtropical forests, but also in tangled scrub, alder Alnus thickets and scrub around habitation. Migrants on the Osumi peninsula were seen in evergreen forest at 850-930 m ¹. It arrives in the Izu Islands in late March or early April and leaves in late September and October.

Threats It is threatened by habitat loss in the Izu Islands. On Miyake-jima, large areas of natural forest have been replaced with the fast-growing softwood Cryptomeria japonica for timber production. Road construction and developments for tourism are damaging its habitat on Miyake-jima and Mikura-jima. On Mikura-jima, there is a long-term plan to relocate a village, or build a new village at Nango, close to an important nesting area. However, the rate of habitat loss in its breeding range does not appear sufficient to account for its recent decline, suggesting that deforestation in its wintering grounds may also be an important threat. Another contributory factor to its decline may be the increased use of pesticides and other agrochemicals in its breeding range. Trapping may also be a threat for migrants passing the Osumi Peninsula¹, and potentially other areas.

Conservation measures underway CMS Appendix II. It is legally protected in Japan. The entire Izu Archipelago has been designated as a national park and several important sites have been designated as Special Protected Areas. However, there are no rangers in the national park, and loss and modification of habitats continues on many islands. There is a small sanctuary on Miyake-jima.

Conservation measures proposed Conduct surveys to clarify its winter distribution. Study the possible impact of pesticide use on the invertebrate prey of this and other species on the Izu Islands. Designate the Mariveles Mountains, Philippines, as a protected area. Maintain and enhance areas of suitable forest and woodland on the Izu Islands. Plan new development on these islands to minimise their negative effects on the habitats of this and other endemic species. Strengthen the human resources of the national park on the Izu Islands. Enforce legal protection in areas affected by trappers.

References BirdLife International (2001). 1. Crystal, F. in litt. (2005).

Further web sources of information

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Text account compilers Phil Benstead (BirdLife International), Simba Chan (Wild Bird Society of Japan), James Gilroy (BirdLife International), Nic Peet (BirdLife International)

Contributors F. Crystal

IUCN Red List evaluators Phil Benstead (BirdLife International), Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Simba Chan (Wild Bird Society of Japan), Nigel Collar (BirdLife International), Mike Crosby (BirdLife International), James Gilroy (BirdLife International), Nic Peet (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Phylloscopus ijimae. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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