Western Water Rail Rallus aquaticus 西方秧雞
Category I. Accidental.
IDENTIFICATION
25-28 cm. Medium-sized rail, with relatively long neck, long, slightly decurved red bill with darker culmen and tip, and dull-red or pinkish legs. Differs from the more common Eastern Water Rail mainly in having no (or only vestigial) dark eye stripe, less extensive white on throat, darker grey underparts lacking brown tinge, and few or no (indistinct) black bars on undertail-coverts. The bill is also usually rather longer and finer, with brighter more extensive red areas.
Care should also be taken to eliminate the superficially similar Slaty-breasted Rail: adults of that species have a shorter, thicker bill, chestnut crown and nape and dark upperparts with fine white bars, while immatures, though less well-marked around the head and neck also have barred upperparts.
VOCALISATIONS
The 2006 bird was heard to utter in alarm a single, short, sharp brief ‘kek’ when flushed by a Grey Heron passing overhead. This corresponds closely to the short ‘kip’ call noted as being given in such situations by this typically rather vocal species with a rich repertoire (Svensson et al. 2009).
DISTRIBUTION & HABITAT PREFERENCE
Has occurred at wetland sites in the northwest New Territories: Long Valley and Mai Po NR.
OCCURRENCE
1998: one on 6 December.
2006: an adult during 2-8 December (Allcock 2011).
BEHAVIOUR, FORAGING & DIET
The bird at Mai Po NR in 2006 was seen feeding at the vegetated edge of a gei wai.
RANGE & SYSTEMATICS
Occurs from Europe and north Africa through west and central Asia to northwest China. Mostly resident in west and central Europe and extreme eastern parts of its range, but a breeding visitor to most of east Europe, west Asia and central Asia, wintering in parts of north Africa, southwest and south Asia (Taylor and Christie 2020). In China, it is a breeding visitor to Xinjiang and has been recorded at scattered locations in the east and southeast suggesting it is a rare winter visitor to these areas (Liu and Chen 2020).
The taxon R. a. korejewi occurs in the easternmost parts of the species’ range and is presumed to be the form that has occurred in HK. Two other subspecies are recognised.
CONSERVATION STATUS
IUCN: Least Concern. Population trend decreasing.
Allcock, J. A. (2011). Western Water Rail Rallus aquaticus at Mai Po. The first Hong Kong record. Hong Kong Bird Report 2007-08: 232-239.
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.
Taylor, B. and D. A. Christie (2020). Water Rail (Rallus aquaticus), 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.watrai1.01