Data Zone
Justification of Red List category
This species has a moderately small population, which is divided into a number of isolated sub-populations, and is likely to be declining as a result of wetland destruction in its breeding and wintering grounds, however recent surveys suggest that the population at Poyang Lake, China, could exceed 5,000 pairs (giving a global population exceeding 10,000 individuals), and the species has consequently been downlisted to Near Threatened.
Population justification
Survey work in Nanjishan National Nature Reserve has estimated a population of c.1,500 pairs in the reserve and at least 5,000 pairs around the lake as a whole (X. Huang et al. in litt. 2007), giving a global population exceeding 10,000 mature individuals but likely below 15,000.
Trend justification
The population is suspected to be declining as a result of habitat degradation and conversion in both breeding and wintering areas.
Locustella pryeri is known to breed at six localities on Honshu, in the prefectures of Aomori, Akita, Ibaraki and Chiba, Japan; in Jiangxi, Jiangsu and probably in Heilongjiang and Liaoning, China, and at Lake Khanka, Russia. Surveys in 2007 at Poyang Lake, Jiangxi, China indicated the presence of a potentially large population, estimated to be up to 5,000 pairs, 1,500 of which are within Nanjishan National Nature Reserve (He Fen-qi et al. 2008, He Fen-qi in litt. 2007, X. Huang in litt. 2007), and it has recently been found breeding on the Yangtze estuary (Jiangsu province) (S. Chan in litt. 2009) and in the Shanghai area (Gan et al. 2006, H. F. Cheung in litt. 2008). In 2001 it was breeding in Japan at Lower Iwaki-gawa (c.37-142 breeding males), Hotokenuma (35-448 breeding males), lower reach of Tonegawa (69-375 breeding males), Byoubusan area (nine singing males) and Ukishima (68-30 individuals in 1998) (Ueda 2003, K. Kato in litt. 2006). Its population at Ogata-sogen (58-122 breeding males in the late 1970s) has declined and recently disappeared (K. Kato in litt. 2006). It winters in Honshu and the Shikoku Islands, Japan and the Yangtze basin, China. There are a few records from eastern Mongolia and South Korea and it almost certainly occurs in North Korea. The population in Japan is estimated to be c.2,500 birds (Ueda 2003, K. Kato in litt. 2006).
Breeding birds prefer dense, mid-height reeds and grasses in shallow water for nesting, with some taller plants for singing posts. It is very sensitive to habitat structure, altering its nest depending on the microhabitat around it (Takahashi et al. 2013), and does not tolerate vegetation that is too short or too tall; and the species has potentially benefited in areas where the average reed height has decreased to a more appropriate height (see Mikami and Takahashi 2013). The spread of cordgrass, Spartina alterniflora, in China may actually be beneficial for this species, as it appears to be key to its survival (and may have facilitated its arrival) at at least one site (Zhijun Ma et al. 2013). Wintering birds favour reedbeds. It is generally very reluctant to fly.
The main threat is the loss and degradation of marshes in its breeding and wintering grounds. Potential breeding sites at Lake Khanka are being converted to agriculture. Wetlands along Nen Jiang river, China, are threatened by oilfield development, reed harvesting for pulp, and alteration of water-levels through irrigation. In the Yangtze basin, wetlands are being destroyed and degraded. In Japan, many breeding sites are in abandoned rice-fields which would be lost if they were brought back into agricultural production. The key breeding site in Japan, Hotoke-numa, is threatened with conversion to pasture. Pollution and hunting are potential threats in China.
Conservation Actions Underway
CMS Appendix II. It is legally protected in reserves in Japan, where breeding sites at Hachiro-gata and Ogata-sogen are protected, and Hotoke-numa was designated as a RAMSAR Site in 2005 (K. Kato in litt. 2006). It has been recorded from protected areas at Lake Khanka (Russia), and Zhalong, Shuangtai Hekou, Poyang Hu and Dong Dongting Hu (China). A large population occurs within the Nanjishan National Nature Reserve (Jiangxi province, China).
14 cm. Medium-sized warbler. Light brownish-buff upperparts with black streaking except on rump and forehead. Indistinct pale supercilium. Buffy-brown tail feathers with dark shafts. Pale buff underparts becoming darker on flanks. Bright buff undertail-coverts.
Text account compilers
Peet, N., Khwaja, N., Butchart, S., Westrip, J., Bird, J., Crosby, M., Symes, A., Benstead, P., Gilroy, J.
Contributors
Kato, K., Huang, X., Cheung, H., Zhijun Ma, Chan, S., He, F.
Recommended citation
BirdLife International (2024) Species factsheet: Marsh Grassbird Helopsaltes pryeri. Downloaded from
https://datazone.birdlife.org/species/factsheet/marsh-grassbird-helopsaltes-pryeri on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.