Justification This species qualifies as Vulnerable because it is likely to have a small, declining population as a result of wetland destruction in its wintering grounds, compounded by limited habitat loss on some islands where it breeds.

Family/Sub-family Sylviidae

Species name author Taczanowski, 1889

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

Identification 13-14 cm. Dull, unstreaked warbler. Uniform olive-grey upperparts with faint, dark mottling on mantle. Indistinct pale cream or grey supercilium with whitish eye-ring. Whitish underparts suffused with pale buff on flanks and sides of breast, although much darker on some birds. Similar spp. Middendorf's Grasshopper Warbler L. ochotensis has browner mantle and scapulars, more noticeable supercilium and eye-stripe and pale outer web to the long, outermost primary. Generally paler underparts.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

2,500-9,999

decreasing

4,100 km²

No

Range & population Locustella pleski is a localised breeder on small islands in Peter the Great Bay in the extreme south of far eastern Russia, the Izu Islands and islands off Kyushu, Japan, and islands off South Korea and probably North Korea. It has also recently been recorded breeding on islands of the coast of eastern China², where it also occurs as a passage migrant, and presumably winters in coastal wetlands in south China, although the only confirmed records are from Hong Kong (China). Recent winter sightings in north-eastern Vietnam suggest that this may also be a significant wintering area³. The population is unlikely to be more than a few thousand individuals, although it is poorly known, as many offshore islands remain unsurveyed and it is relatively difficult to detect.

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

Ecology: It breeds in open, wet areas of thick grasses and reeds and in areas of low bushes. In its wintering range, birds have been found in extensive reedbeds, low shrubs near reedbeds and mangroves. It probably holds territories in winter. On the Izu Islands, it breeds from May-June with clutch-sizes ranging from 3 to 6 eggs. It is skulking and reluctant to fly.

Threats The main threat is likely to be habitat loss and degradation, although the extent to which this is affecting it is currently unclear. In Russia, and possibly North Korea, the large-scale Tumangan Project could lead to increased human disturbance and pollution, possibly affecting islands where it breeds. A camping ground or marine park is planned for Toga Point on Miyake-jima (Izu Islands), which would destroy an important area of habitat. A volcanic eruption on Myiake-jima in 2000 lead to a halving of the population on that island¹. There is continued extensive loss of wetlands in its wintering range and the reedbeds in Deep Bay, Hong Kong, may be one of the largest areas of such habitat left in south China.

Conservation measures underway CMS Appendix II. One of its wintering sites is protected at the Mai Po Marshes Nature Reserve, which is also included inside the Mai Po Marshes Ramsar Site. A long-term ringing programme at this site has contributed to knowledge of its winter habitat requirements and abundance.

Conservation measures proposed Survey small islands within its potential breeding range and suitable habitat within its wintering range to clarify its population, distribution, habitat requirements and threats. Extend the boundaries of the Far Eastern Marine Reserve, in Peter the Great Bay (Russia), to include islets where it breeds. Strengthen protection of buffer zones around Mai Po Marshes Nature Reserve and control development where possible.

References BirdLife International (2001). 1. Fujita et al. (2005). 2. Yi-Lun et al. (2006). 3. J. Pilgrim in litt. (2008).

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), James Gilroy (BirdLife International), Nic Peet (BirdLife International)

Contributors John Pilgrim (BirdLife International)

IUCN Red List evaluators Phil Benstead (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: Locustella pleskei. 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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