Chinese Leaf Warbler Phylloscopus yunnanensis 雲南柳鶯
Category I. Accidental.
IDENTIFICATION
Nov. 2020, Michelle and Peter Wong.
9-10 cm. Like Pallas’s Leaf Warbler but differs in being generally duller and in having a structure that is intermediate with Yellow-browed Warbler and, critically, a finer bill. The central crown stripe is poorly-marked at the front of the head, usually failing to reach the bill, while the lateral crown stripes can vary from relatively pale to dark. The supercilium has no yellow tinge (though is buffer toward the rear) and the eye stripe is dark.
The secondaries are edged pale to the base and no dark bar appears below the greater coverts in the closed wing. The greater coverts are dark with contrasting and clear-cut pale tips forming a distinct wing bar, while the median coverts form a much less noticeable wing bar. The inner two tertials are edged whitish on the outer webs. The pale rump is duller and appears smaller than that on Pallas’s Leaf Warbler (Alström 2020). Call is noticeably different from both its congeners (see below).
VOCALISATIONS
The usual non-breeding season vocalisation heard in HK is a moderately high-pitched but sharply rising ‘tueet’ that is reminiscent of Fork-tailed Sunbird in pitch and delivery. However, it differs in being approximately 30% shorter in duration, less musical, fuller and of a consistent character across the note, thus lacking a slightly breathy beginning.
DISTRIBUTION & HABITAT PREFERENCE
All birds have occurred in closed canopy evergreen broadleaf secondary forest and shrubland.
OCCURRENCE
All records are of single birds as follows.
1997: trapped at Kadoorie Farm and Botanic Garden on 4 March (Leven 1999).
2002: trapped at Kadoorie Farm and Botanic Garden on 3 November.
2008: seen at Pak Sha O on 28 December.
2015: seen at Lam Tsuen on 9 February.
2016: seen and recorded at Tai Lam Country Park on 13 November.
2020: seen and recorded at Tai Po Kau during 16-17 November.
BEHAVIOUR, FORAGING & DIET
Forages for insects in the manner of Pallas’s Leaf Warbler, though perhaps not in quite as lively a manner nor as actively, and possibly hovers less.
RANGE & SYSTEMATICS
Monotypic. Breeding range is endemic to China from northeast Qinghai east through south Gansu, Shaanxi, Shanxi and north Hebei and south to Sichuan; non-breeding range unclear, but includes south and southwest Yunnan (China), north Thailand and adjacent parts of Myanmar and Laos; vagrants have also occurred in Shanghai and Taiwan (Alström 2020, Liu and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Alström, P. (2020). Chinese Leaf Warbler (Phylloscopus yunnanensis), 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.chilew1.01
Leven, M. R. (1999). Chinese Leaf Warbler: the first record for Hong Kong. Hong Kong Bird Report 1997: 120-127.
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.
