White-spectacled Warbler Phylloscopus intermedius 白眶鶲鶯
Category I. Scarce winter visitor to closed-canopy forest.
IDENTIFICATION
Jan. 2021, Roman Lo.
Based on Leader and Carey (2016), the most straightforward of this group to identify based on plumage due to the obvious break in the orbital ring above the front portion of the eye (care needed to rule out angle of view as cause), obvious yellow wing bar and rich yellow underparts. The orbital ring tends to be broad, the dark lateral crown stripes distinct and the bill slightly shorter and thinner than other taxa. Call is diagnostic (see below).
Jan. 2011, Michelle and Peter Wong.
The ‘cognitus’ morph on the head lacks some or all grey, which is replaced by olive-green; presumed intermediates retain grey on the crown (as in this photograph).
VOCALISATIONS
The call is richer and more whistled than other species in this group occurring in HK. It also differs from most in being clearly multi-syllabic; compared to the bi-syllabic call of Plain-tailed Warbler it is lower in pitch.
DISTRIBUTION & HABITAT PREFERENCE
Generally, occurs in closed-canopy woodland. Most records are from the Tai Mo Shan massif but has also occurred at other widespread areas including Po Toi, Cheung Chau and HK Island.
OCCURRENCE
First recorded on 17 November 2002 (Wong and Wong 2009), White-spectacled Warbler has proved to be a scarce winter visitor with extreme dates of 8 November and 5 March. The main period of occurrence is from the third week of November to the third week of February (Figure 1). Usually recorded singly, occasionally two are together. The green-headed ‘cognitus’ morph is less common, with approximately 12 reports.
Lack of knowledge regarding the identification of members of the ‘golden-spectacled’ group of warblers means that before 2002, only in-hand records can be assigned to species.
BEHAVIOUR, FORAGING & DIET
Forages unobtrusively in the understorey, occasionally making short flights to take insect prey on the vegetation or in the air. Often adopts a rather horizontal posture.
RANGE & SYSTEMATICS
Breeds from east Himalayas east to southeast China and south to south Vietnam. The nominate taxon, which has a yellow orbital ring, breeds in central and southeast China and occurs in HK. P. i. zosterops occurs to the west, while P. i. ocularis occurs in south Vietnam; these two taxa are indistinguishable. In China occurs in areas south of the Yangtze (Alström 2020, Liu and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Figure 1.
Alström, P. (2020). White-spectacled Warbler (Phylloscopus intermedius), 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.whswar1.01
Leader, P. J. and G. J. Carey (2016). The identification of Seicercus warblers in Hong Kong. Hong Kong Bird Report 2014: 322-333.
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.
Wong, P. and Wong, M. (2009). White-spectacled Warbler Seicercus affinis at Tai Po Kau: the first record for Hong Kong. Hong Kong Bird Report 2003-04: 218-221.
