IDENTIFICATION

VOCALISATIONS

The male gives a distinctive whistled ‘whee-yoorr’ at rest or in flight.

The female utters a quiet low-pitched throaty ‘krrr-krrr’ mostly when flushed.

DISTRIBUTION & HABITAT PREFERENCE

Eurasian Wigeon occurs in both brackish and freshwater wetland areas including intertidal mudflats, more vegetated areas on Mai Po NR and commercial fish ponds. The great majority of records are from Inner Deep Bay and its hinterland as far as the hills, including all fish pond areas and Long Valley, and outer Deep Bay as far Pak Nai with very few elsewhere. At Long Valley it is recorded nearly annually, with the highest count being seven on 15 December 2015.

The highest count away from these areas are of up to 215 at Tai Lam Chung on 6th and 13 March 1971, with 80 there during 28-29 January 1973; these were exceptional, however. Other records have occurred in scattered coastal localities, mostly involving singles, and there are only two records from Lantau, where up to three have been seen at Pui O. The highest of these counts away from the north and northwest New Territories counts is of 17 birds in flight over the sea in the vicinity of the airport on 7 February 2015.

OCCURRENCE

Eurasian Wigeon is an abundant winter visitor mainly from October to April, with no double-figure counts from mid-April to the end of September (very few records in June and July) and few triple-figure counts before the end of October. November sees the main arrival of birds, and peak numbers occur during December to February.

Figure 1 indicates that numbers in the whole of Deep Bay were relatively low until the mid-1990s when there was an increase to 4,000, followed by a steep rise to 6,705 in winter 2000/01; this total was not exceeded until winter 2020/21 when 6,949 were recorded. On the Hong Kong side of Deep Bay numbers have broadly followed the whole bay trend, with the highest count being 5,483 on 21 February 2021. In general, over 70% of Eurasian Wigeon are present on the HK side of Deep Bay, although in the winter periods of the highest counts this figure is generally lower.

Although Sung et al. (2021) found that Eurasian Wigeon was one of four duck species whose populations in Deep Bay declined from 1998 to 2017, it was only after this time period that a substantial increase in the number of wintering birds has occurred.

Eurasian Wigeon was noted by Kershaw (1904) as ‘common in winter’, while Vaughan and Jones (1913) reported it as being present from 11 October to 25 February, though without mentioning a specific locality. Dove and Goodhart (1955) reported a record of 17 birds on 3 April at Mai Po as the first for HK, though that seems unlikely. Macfarlane and Macdonald (1966) stated that the species was recorded on several occasions in Deep Bay from September to April. It is likely that hunting acted as a significant deterrent to its presence until its prohibition in the early 1980s.

BEHAVIOUR, FORAGING & DIET

Appears to be largely vegetarian and grazes on algae more than other species. Although large flocks are seen in the intertidal areas of Deep Bay, only small to moderate flocks occur inland.

RANGE & SYSTEMATICS

Monotypic. Breeds from Iceland and northern Europe east across Eurasia to the Bering Sea; in winter reaches southern Europe and north Africa, the Middle East, the northern half of the Indian subcontinent east to Japan (Carboneras et al. 2020). In China breeds in the northeast and winters south of the Yellow River, including Hainan and Taiwan (Yang and Chen 2020).

CONSERVATION STATUS

IUCN: Least Concern. Population trend decreasing.

Eurasian Wigeon was one of four duck species identified by Sung et al. (2021) to have declined in the period 1998-2017. Since then, however, numbers in HK have increased. The East Asian wintering population is estimated at 500,000 to 1,000,000 birds and considered to be increasing in the period 2011-2020 (Wetlands International 2022).