Blunt-winged Warbler Acrocephalus concinens 鈍翅葦鶯
Category I. Rare winter visitor to reed marsh and wetland vegetation.
IDENTIFICATION
Oct. 2011, Paul Leader.
13 cm. Rather nondescript. Separated from Black-browed Reed Warbler by lack of obvious dark border above a short supercilium that is mainly above and in front of eye, no eye stripe behind eye and shorter wings and primary projection. Upperparts rufous in tone, especially rump, and closed wing fairly uniform with darker alula. Tertials have broad rufous fringes in fresh plumage, fading to sandy-brown when worn. Bill is typically long and deeply based (Kennerley and Leader 1992).
VOCALISATIONS
A fairly harsh ‘chek’ and a longer, buzzing ‘zrrrt’.
The song is relatively slow-paced and includes whistles and buzzing elements but rather few churrs.
DISTRIBUTION & HABITAT PREFERENCE
All birds have occurred in reed marsh.
OCCURRENCE
From the first record on 20 April 1991 (Leader 1992) to the end of 2020 there were 20 records of Blunt-winged Warbler, most of which appeared in mist nets in the reed bed at Mai Po NR. The earliest appeared on 6 September 2005, more than one month earlier than the next earliest on 17 October 2005; the latest was also the first record, a male in song during 20-21 April 1991. November to February is the main period of occurrence.
BEHAVIOUR, FORAGING & DIET
Shy and skulking, may be present in a small area of reeds but not show itself for long periods.
RANGE & SYSTEMATICS
There are three disjunct populations. A. c. haringtoni breeds from north Afghanistan east to Kashmir; these birds probably winter nearby in the Himalayan foothills. The second is A. c. stevensi, which breeds in northeast India and adjacent parts of Bangladesh and Myanmar, and winters nearby at lower altitudes. The third breeding population consists of the nominate subspecies whose breeding range is confined to China, where it is a summer visitor from Hebei south to Fujian and west to Guangxi; these birds winter in south and southwest China and in north Indochina (Dyrcz 2020, Liu and Chen 2020, Kennerley and Pearson 2010).
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Dyrcz, A. (2020). Blunt-winged Warbler (Acrocephalus concinens), version 1.0. 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.blwwar1.01.
Kennerley, P. R. and P. J. Leader (1992). The identification, status and distribution of small Acrocephalus warblers in eastern China. Hong Kong Bird Report 1991: 143-187.
Kennerley, P. and D. Pearson (2010). Reed and Bush Warblers. Christopher Helm, London.
Leader, P. J. (1992). Blunt-winged Warbler: a new species for Hong Kong. Hong Kong Bird Report 1991: 120-122.
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.
