Chestnut-crowned Warbler Phylloscopus castaniceps 栗頭鶲鶯
Category I. Scarce winter visitor to closed-canopy woodland and shrubland.
IDENTIFICATION
Dec. 2010, Michelle and Peter Wong.
9-10.5 cm. Tiny warbler, unmistakable if seen well. Chestnut crown with subdued dark lateral crown lines, distinct white orbital ring broken at top, grey face and chest, lemon yellow chest to undertail coverts and edges to remiges.
Jan. 2020, Roman Lo.
From above shows grey hind neck, lime green mantle, pale yellow rump and wing bars.
VOCALISATIONS
Calls include a short dry rattle that is also uttered in alarm, and a quiet, fairly high-pitched ‘tit’; both are audible in this recording.
The song is rarely reported, though this may be due to its being quiet and inconspicuous.
DISTRIBUTION & HABITAT PREFERENCE
Occurs in closed-canopy forest, with 75% of reports from Tai Po Kau and other sites on the Tai Mo Shan massif. Also reported from the Tai Lam area, northeast New Territories, Sai Kung, and the islands of HK, Lantau, Po Toi and Cheung Chau.
OCCURRENCE
Scarce winter visitor from the second week of November to the second week of March, but mainly from December to February (Figure 1). Extreme dates are 5 November 1988 and 15 March 2017. The peak in the final week of December is probably an artefact of increased observer activity at that time.
Most reports are of single birds apart from up to three in November and December 2004 and two on 11 January 1992, all at Tai Po Kau.
BEHAVIOUR, FORAGING & DIET
Highly active as it forages in dense canopy or tangles, often flicking its wings and fanning its tail. Joins mixed species flocks but also forages alone. The quiet, high-pitched song may be heard in early spring, though it is easy to overlook.
RANGE & SYSTEMATICS
Breeds from the Himalayas east to central and south China and south through montane areas of Indochina, peninsular Malaysia and Sumatra; most populations are resident. In China breeds in montane areas south of the Yellow River but not as far as the south coast; northerly populations are migratory, with most birds probably wintering in south and southwest China (Madge 2020, Liu and Chen 2020).
The taxon P. c. sinensis, identified by more extensive yellow on the underparts, occurs in much of China, including HK. Eight other subspecies are recognised.
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Figure 1.
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. (2020). Chestnut-crowned Warbler (Phylloscopus castaniceps), 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.chcwar2.01
