Indian Spot-billed Duck Anas poecilorhyncha 印缅斑嘴鴨
Category I. Previously a scarce resident but now apparently absent, with no certain records since 2012.
IDENTIFICATION
Jul. 2003, Michelle and Peter Wong.
58-63 cm. A large dabbling duck that at rest is overall dark brown with a pale head and chest, largely white tertials, white tipped greater coverts and orange legs. Similar to Eastern Spot-billed Duck but slightly smaller and slighter in build, lacks rather broad whitish supercilium and any hint of dark cheek bar and has paler underparts. Pale brown face, including supercilium, with contrasting dark crown and eye stripe, broad yellow tip to bill with black tip. In flight underwing coverts are white and speculum appears either blue or green, depending on the angle, bordered both sides by white feather tips.
May 2006, Kinni Ho.
Juveniles are distinguished from Chinese Spot-billed Duck by the lack of dark marking below the rear of the eye and at the base of the bill.
VOCALISATIONS
Similar to those of Mallard or Eastern Spot-billed Duck.
DISTRIBUTION & HABITAT PREFERENCE
The majority of records are from Mai Po NR, with only one of these from the intertidal mudflats. There are two records elsewhere, one from nearby Wo Shang Wai and the second from HK Wetland Park, both outside the breeding season. It largely occurs in freshwater marsh or ponds.
OCCURRENCE
The presence of Indian Spot-billed Duck in Hong Kong was first reported in 1974 but it was not widely known until December 1993 (Carey and Melville 1996). Carey et al. (2001) stated it was ‘certainly present all year … and would appear to be largely resident’. The peak winter count reported was 19 on 19 November 1997 and the peak autumn count 40 on 7 October 1997. Subsequently, however, the highest count was 16 on 28 July 2003, after when no count higher than six was made. It continued to be reported regularly, if infrequently, until October 2005, and then three or four times a year in 2007, 2009 and 2012, but 25 August 2012 is the last date on which it was recorded.
While there seems little doubt that Indian Spot-billed Duck was overlooked prior to the mid-1990s, the lack of records since 2012 suggests that its occurrence here is erratic and possibly influenced by natural expansion and contraction of its range. HK and Guangdong are some distance from its core area of occurrence in Indochina and Yunnan, and it may be that it occurs in this area of China erratically.
BREEDING
Display has been noted in February, copulation on 9 April and 6 September, a female with seven chicks on 24 June and fledged juvenile on 28 May. Leader (2006) recorded eleven pairs of Indian Spot-billed Duck in 1994 and 1997 to 2005, as well as two mixed pairs comprising male Indian with female Chinese Spot-billed Duck and male Indian with an apparent hybrid Indian x Chinese female. Only one in ten pairs were mixed pairs, and the hybrid female is the only record of such an individual (Leader 2006).
BEHAVIOUR, FORAGING & DIET
Occurs in both single-species groups and together with Chinese Spot-billed Duck.
RANGE & SYSTEMATICS
Two subspecies are recognised. A.p. haringtoni occurs from east Assam east through Myanmar and Indochina to south China, including HK. The nominate subspecies occurs further west.
Largely resident in lowland areas from India east through Myanmar to Indochina and southwest China. In China A.p. haringtoni is reported by Liu and Chen (2020) to be locally common in west and south Yunnan and accidental in Guangdong and HK. Carey and Melville (1996) report one, possibly two specimens from Guangdong in the British Museum. The first was collected by Vaughan at ‘Sam Shui’ on 5 April 1905, though it was not subsequently referred to in Vaughan and Jones (1913). The second is labelled Canton, China, though it is unclear if it was shot or obtained from the bird market.
CONSERVATION STATUS
IUCN: Least Concern. Population trend decreasing.
Carey, G. J. and D. S. Melville (1996). Spot-billed Ducks in Hong Kong. Hong Kong Bird Report 1995: 224-230.
Carey, G. J., M. L. Chalmers, D. A. Diskin, P. R. Kennerley, P. J. Leader, M. R. Leven, R. W. Lewthwaite, D. S. Melville, M. Turnbull and L. Young (2001). The Avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.
Leader, P. J. (2006). Sympatric breeding of two Spot-billed Duck Anas poecilorhyncha taxa in southern China. Bull. B.O.C. 2006 126(4): 248-251.
Vaughan, R. E. and K. H. Jones (1913). The birds of Hong Kong, Macao and the West River or Si Kiang in South-East China, with special reference to their nidification and seasonal movements. Ibis 1913: 17-76, 163-201, 351-384.
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.
