Greenish Warbler Phylloscopus trochiloides 暗綠柳鶯
Category I. Accidental.
IDENTIFICATION
Nov. 2020, Roman Lo.
10-11.5 cm. Plain upperparts and tertials, short greater covert wing bar tapered at each end, yellowish tone to upperparts and underparts, long whitish supercilium extending from base of bill, loral spot in front of eye separate from bill, largely pale lower mandible. Call distinctive (see below).
VOCALISATIONS
The call of viridanus is simpler and less full than that of Two-barred Warbler and resembles more the call of Hume’s Leaf Warbler. Song has also been heard from birds in November and May. Both can be heard in this recording.
DISTRIBUTION & HABITAT PREFERENCE
Records have occurred in lightly and densely wooded areas.
OCCURRENCE
2015: one at Tai O from 18 December to 8 January 2016 (Allcock 2017).
2016: one at Ng Tung Chai on 2 May.
2020: one at Luk Keng from during 1-4 November.
2021: one at Tung Lung Chau on 9 April.
BEHAVIOUR, FORAGING & DIET
More lively foraging behaviour than Arctic Warbler.
RANGE & SYSTEMATICS
Four subspecies are recognised (though not by all authorities), the most widespread of which is P. t. viridanus, which breeds from east Europe through Siberia to northwest China; based on call, this is the taxon that is considered to occur in HK. The three remaining subspecies are P. t. ludlowi in north Pakistan and the northwest Himalayas, P. t. trochiloides in from the central Himalayas east to south central China, and P. t. obscuratus in central China (Liu and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend increasing.
Allcock, J. A. (2017). Greenish Warbler of the subspecies viridanus Phylloscopus trochiloides viridanus at Tai O. The first Hong Kong record. Hong Kong Bird Report 2015: 288-295.
Clement, P. (2020). Greenish Warbler (Phylloscopus trochiloides), 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.grewar3.01.
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.
