IDENTIFICATION

VOCALISATIONS

Generally silent away from the breeding grounds. On flying the female utters an inflected, slightly nasal note.

DISTRIBUTION & HABITAT PREFERENCE

In the first phase of occurrence up to 1989 (see below) records were quite scattered and locations included both reservoirs and sites in the Deep Bay area. Records in the third phase have also been scattered, though none have occurred on reservoirs despite the fact that the wooded margins of some of these might be considered suitable habitat. However, certain other waterfowl were previously, if occasionally, recorded on reservoirs historically but are not now.

In the third and most recent phase most records have occurred in the northern New Territories in the area from Kam Tin through Mai Po NR to Long Valley; however, there have also been records at Lam Tsuen, Nam Chung, Penfold Park, Po Toi, Shing Mun River, Tai Po Kau and Tsing Tam Reservoir. Habitats include freshwater and brackish ponds, channelised watercourses both wide and narrow, natural watercourse in or near forest and small water bodies in a semi-urban park.

OCCURRENCE

As with Lesser Whistling Duck, the pattern of occurrence of divides itself into three phases, the first of which is the period up to the end of 1989. Dove and Goodhart (1955) reported a male shot near Luen Tak on 26 October 1952 and a female shot near Shek Kong in April 1953, though they also stated that without a specimen these had to be regarded as ‘doubtful records’; Macfarlane and Macdonald (1966) reported two occasions on which one of a pair seen was shot: in Tolo Harbour in November 1958 and at Sheung Shui on 2 November 1962. Carvalho (1973) reported it as ‘rare’ with the largest group being seven immatures, two of which were shot at Mong Tseng in 1959 (it is assumed the reference to ‘immatures’ means females or immatures, as the separation of the two is not straightforward). Subsequently, up to 1989 there were five records, as follows:

• a pair at Tai Lam Chung Reservoir on 5 December 1959.
• a female at Tuen Mun on 23 October 1976.
• a female at Tai Tam between 7 January and 25 March 1984.
• a female at Mai Po on 31 March 1986.
• a female at Mai Po from 29 November to 26 December 1989.

These records are considered to relate to birds of natural occurrence as all occurred prior to the establishment at Mai Po NR in December 1989 and January 1990 of a captive waterfowl collection in which a small feral population developed.

Subsequently in the second phase there was a series of records in the 1990s in the waterfowl collection or its immediate vicinity, all of which are considered likely to relate to this feral population. The only other record occurred on 6 November 1995 at a park in Sha Tin, though the source of this bird remains uncertain. The last record in the 1990s occurred on 22 April 1999 when a pair were seen at Mai Po NR.

The absence of records from 1999 to 2007 is evidence that the feral population at Mai Po died out, and subsequent records constitute the third phase. In the final phase there have been records of birds showing physical signs of previous captivity in the form of rings on the legs or damage to flight feathers and behavioural signs in allowing close approach; however, there have also been birds that have shown none of these.

Excluding birds considered to have possibly been of captive origin, historically records have occurred over the winter period from 26 September to 31 March (though no later than 5 February this century), apart from 2019 when a male was present at Mai Po NR on 16 June and 1 July, and up to two males were seen at Long Valley from 12 August to 1 September; these may refer to the same birds. It is, of course, impossible to be sure that any of these records involve birds not previously captive at some stage, but the weight of evidence suggests that wild birds do arrive here unaided.

BEHAVIOUR, FORAGING AND DIET

Some birds are rather approachable. To some extent this may reflect previous captivity, but it is not necessarily the case.

RANGE & SYSTEMATICS

Monotypic. Breeds northeast China as far south as Beijing, Ussuriland and southern Kamchatka, and occurs year-round in Japan and Taiwan (Carboneras and Kirwan 2020); elsewhere in non-breeding season largely confined to China, where it occurs at low densities in most areas south of Beijing (Birding Beijing 2021, Liu and Chen 2020).

CONSERVATION STATUS

IUCN: Least Concern. Population trend decreasing.