Willow Warbler Phylloscopus trochilus 歐柳鶯
Category I. Accidental.
IDENTIFICATION
Oct. 2020, Paul Leader.
11-12.5 cm. Plain Phylloscopus warbler with long primary projection equal to length of exposed tertials, brownish-pink legs, greyish-green upperparts, long whitish supercilium and no wing bar. Immatures in autumn are yellowish below, while adults in spring are whiter.
VOCALISATIONS
The call is a sharply upslurred ‘hooeet’.
DISTRIBUTION & HABITAT PREFERENCE
Both birds occurred in open country habitat near wetland areas in the northwest New Territories.
OCCURRENCE
2008: one at Long Valley on 25 October (Chu 2011)
2020: one trapped at Mai Po NR on 19 October.
BEHAVIOUR, FORAGING & DIET
No observations.
SYSTEMATICS & RANGE
Three subspecies are recognised across its pan-Eurasian breeding distribution. P. t. yakutensis is presumed to have occurred in HK as it breeds in central and east Siberia. P. t. acredula breeds from Scandinavia (excluding Sweden) to east Europe and west Siberia, while the nominate breeds in south Sweden and west and central Europe. All taxa winter in sub-Saharan Africa. In China migrants have been recorded in Xinjiang, Qinghai and Nei Mongol (Liu and Chen 2020), and vagrants have occurred on the Hebei coast (COS 2007) and Taiwan (Ding et al. 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend decreasing.
Chu, F. (2011). Willow Warbler Phylloscopus trochilus at Long Valley. The first Hong Kong record. Hong Kong Bird Report 2007-08: 261-262.
C. O. S. (China Ornithological Society) (2007). China Bird Report 2006. China Ornithological Society, Beijing.
Liu, Y. and Chen, Y. H. (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Ding, T. S., Juan, C. S., Lin, R. S., Tsai, Y. J., Wu, J. L., Wu, J. and Yang, Y. H. (2020). The 2020 CWBF Checklist of the Birds of Taiwan. Bird Record Committee, Chinese Wild Bird Federation, Taipei. Downloaded at: https://www.bird.org.tw/report/2020/english
