Sulphur-breasted Warbler Phylloscopus ricketti 黑眉柳鶯
Category I. Scarce winter visitor to closed-canopy forest.
IDENTIFICATION
Oct. 2015, Michelle and Peter Wong.
10-11 cm. Has striking blackish lateral crown and eye stripes, boldest toward rear, contrasting with yellowish coronal stripe, supercilium. Greater coverts tipped whitish forming obvious wing bar, median covert wing bar often narrow or difficult to see. Pale edges to outer two tail feathers. Upperparts rather bright olive-green.
Mar. 2018, Michelle and Peter Wong.
Differs from the nominate form of Hartert’s Warbler in having entire underparts uniform yellow (tinged greenish on flanks) and very contrasting dark stripes on head.
VOCALISATIONS
The call, which appears to be rarely uttered, is a disyllabic, moderately high-pitched ‘pitch-yoo’ with the second syllable downslurred. Similar to the call of Hartert’s Leaf Warbler, it may be overlooked for that reason.
DISTRIBUTION & HABITAT PREFERENCE
Largely recorded in closed-canopy forest in the Tai Mo Shan massif and Tai Lam but occurs elsewhere in the New Territories and both HK and Lantau Islands, including urban edge areas such as Ho Man Tin and Wanchai.
OCCURRENCE
Although previously on the HK List (Chalmers 1986), Sulphur-breasted Warbler was removed due to confusion with the nominate subspecies of Hartert’s Warbler, which also has yellow on the underparts. Consequently, the first adequately substantiated record is of a bird in Tai Po Kau on 25 November 2005 (Kwan 2010). Familiarity with the appearance of the species has increased and it is now recorded every winter period.
Extreme dates are 13 September 2020 and 1 April 2006, while the main period of occurrence is mid-November to early February (Figure 1), though this is based on a relatively small number of records. Usually recorded singly, the highest count is of four at Tai Po Kau on 24 December 2008.
BEHAVIOUR, FORAGING & DIET
Forages largely in the canopy but also down to head height. Occurs both alone and in mixed flocks. Makes somewhat slower progress than Yellow-browed Warbler.
RANGE & SYSTEMATICS
Monotypic. Largely a Chinese breeding endemic in low montane areas of China south of the Yellow River; winters to the southwest into Indochina (Clement 2020, Liu and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Figure 1.
Chalmers, M.L. (1986). Annotated Checklist of the Birds of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.
Clement, P. (2020). Sulphur-breasted Warbler (Phylloscopus ricketti), 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.subwar3.01.
Kwan, P. K. (2010). Sulphur-breasted Warbler Phylloscopus ricketti at Tai Po Kau: the first Hong Kong record. Hong Kong Bird Report 2005-06: 209-211.
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.
