Marsh Grassbird Helopsaltes pryeri 斑背大尾鶯
Category I. Accidental.
IDENTIFICATION
Dec. 2009, John Allcock.
12-14 cm. Proportionately long and full tail, short wings and short, stubby, largely pale bill. Bare greyish lores, pencil thin eye stripe behind eye, large black centres to tertials and rufous-brown crown to upper tail coverts broadly streaked black are diagnostic in a HK context.
VOCALISATIONS
The call heard in HK in response to pishing is a soft ‘chit’ or ‘chert’.
The song is fairly measured flat trill given in short bursts.
DISTRIBUTION & HABITAT PREFERENCE
Most birds have been found in mist nets in reed marsh at Mai Po NR, with the only bird not trapped occurring in dense tall grass.
OCCURRENCE
All records are of single birds.
2007: trapped at Mai Po NR on 10 November.
2009: trapped at Mai Po NR on 11 December.
2010: trapped at Mai Po NR on 2 December, retrapped on 6th and 14 December.
2011: at Sai Sha on 19 January.
2012: trapped at Mai Po NR on 23 November.
2019: trapped at HK Wetland Park on 12 February.
BEHAVIOUR, FORAGING & DIET
Shy, skulking and difficult to see.
RANGE & SYSTEMATICS
H. p. sinensis breeds from northeast Mongolia through northeast China to Primorskiy and also along the lower reaches of the Yangtze and on Chongming Island (Liu and Chen 2020, He et al. 2008). The nominate subspecies is endemic to Japan, breeding in north and east Honshu (Madge 2021).
CONSERVATION STATUS
IUCN: NEAR-THREATENED. Population size 10,000 to 15,000 and likely to be decreasing due to wetland destruction in breeding and wintering areas.
He, F. Q., J. S. Lin, X. J. Huang and W. X. Dong (2008). Preliminary report on the Poyang Lake breeding subpopulation of the Marsh Grassbird in Jiangxi, central south China. Chinese J. Zool. 43: 70-72 (in Chinese).
Leader, P. J., J. A. Allcock, D. Stanton and K. Leung (2011). Japanese Swamp Warbler Locustella pryeri at Mai Po. The first Hong Kong record. Hong Kong Bird Report 2007-08: 270-272.
Liu, Y. and Y. H. Chen (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Madge, S. (2021). Marsh Grassbird (Helopsaltes pryeri), version 1.1. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.margra1.01.1
