Northern Pintail Anas acuta 針尾鴨
Category I. An abundant winter visitor to the Deep Bay area, though numbers are much lower than in the 1990s.
IDENTIFICATION
Mar. 2007, James Lam. Male (left) and female.
51-62 cm. Large but slim with a long neck and tail (particularly in the male). In breeding plumage male has dark brown face and hind neck with distinctive tapering white line extending from the white throat up the side of head. Central part of underbody white, flanks grey, black undertail coverts, long black scapulars with broad buff fringes. Legs and bill grey, latter with dark culmen.
Female has slim grey bill, a rather plain brownish head contrasting with body. Eclipse male as adult female apart from upperwing, which is as adult male, and longer and less brown scapulars.
Jan. 2012, CHUNG Yun Tak. Adult male eclipse.
In flight both sexes have long and narrow wings and neck and a dark speculum that is white at the rear. On the male the speculum is bordered buff at the front, while on the female this is narrowly white.
VOCALISATIONS
Male utters a ‘prrip’ similar to Common Teal simultaneous and a modulated nasal ‘sweee-swee’.
Female utters a ‘keh-kuk’ or ‘kuk’ quacking call.
DISTRIBUTION & HABITAT PREFERENCE
Occurs throughout the Deep Bay area from Nim Wan to Hoo Hok Wai inland along Kam Tin River as far as Kam Tin. The bulk of wintering birds occur in the intertidal areas of Inner Deep Bay, although high numbers sometimes roost in Mai Po NR, particularly in 2005-07 when the highest count was 4,647; generally, however, three-figure totals are recorded in the reserve. Northern Pintail is rare in commercial fish ponds.
For such an abundant duck, records away from the Deep Bay area are remarkably few. At Long Valley up to five have been recorded; in recent years, single-figure counts have been made in the Starling Inlet / Nam Chung area, at Shuen Wan and on single occasions on Lam Tsuen River and at Pui O, Lantau. Most of these records have occurred in late autumn and early winter.
Away from these sites, the only records are of 80 at Tide Cove on 4 October 1959, one at Kai Tak on 26 October 1978, 17 in Castle Peak Bay on 19 February 1978, and three at Kowloon Reservoir on 30 November 1995.
OCCURRENCE
Northern Pintail, usually one of the two most numerous ducks in Deep Bay, is an abundant winter visitor generally present from the last week in September to the third week of April; extreme dates are 14 September 2004 and 22 May 1989, though the latest this century occurred on 22 April. There are only two records of presumed over-summering birds: in 1984 and 1989.
The highest count on the HK side of Deep Bay is 8,086 on 15 January 2000, while the highest whole Deep Bay count is 8,651 on 11 January 1997. Figure 1 indicates that from winter 1990/91 to 1999/2000 more than 5,000 birds were generally recorded in winter waterbird counts; however, since winter 2000/01 fewer than 5,000 birds have been present, and in the most recent three winter periods less than 2,000. Based on winter waterbird counts in Deep Bay Sung et al. (2021) concluded that the wintering population declined from 1998 to 2017.
Vaughan and Jones (1913) referred to the presence of Northern Pintails at Guangzhou and their habit of feeding in paddy fields at night. La Touche (1931-34) stated that Northern Pintail was abundant in southeast China, while Herklots (1967) referred to it as one of the commonest ducks in winter on the coast of eastern China. In contrast, Macfarlane and Macdonald (1966) stated that there were only occasional autumn and winter records of up to 70 birds from Hong Kong between 28 September and 18 February.
BEHAVIOUR, FORAGING & DIET
A gregarious species that is often in large flocks in Inner Deep Bay; large numbers may also roost in Mai Po NR. Pair formation takes place in the second half of the winter.
RANGE & SYSTEMATICS
Monotypic. Holarctic breeding species breeding across much of the northern hemisphere between approximately 40°N and 70°N, apart from northwest and western Europe. Winters to the south and west as far as extreme northwest South America, central and east Africa, Sri Lanka and northern Indochina. In China it is a migrant in the northwest and northeast and winters along the lower and middle reaches of the Yangtze River and in scattered areas of south China to the coast, including Hainan and Taiwan (Yang and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend decreasing.
Northern Pintail was one of four duck species identified by Sung et al. (2021) to have declined in the period 1998-2017, a trend that seems to have continued since. The East and Southeast Asian wintering population is estimated at 200,000 to 300,000 birds and considered to be possibly stable in the period 2011-2020 (Wetlands International 2022).
Figure 1.
Herklots, G. A. C. (1967). Hong Kong Birds (2nd ed.). South China Morning Post, Hong Kong.
La Touche, J. D. D. (1931-34). Handbook of the birds of Eastern China Vol. 2. Taylor and Francis, London.
Macfarlane, A. M. and A. D. Macdonald, revised by Caunter, J. R. L. and A. M. Macfarlane (1966). An Annotated Check-list of the Birds of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.
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.
Sung, Y. H., C. C. Pang, T. C. H. Li, P. P. Y. Wong and Y. T Yu (2021). Ecological Correlates of 20-Year Population Trends of Wintering Waterbirds in Deep Bay, South China. Frontiers in Ecology and Evolution. Published 20 April 2021 doi: 10.3389/fevo.2021.658084
Wetlands International (2022). Waterbirds Populations Portal. Available at: https://wpp.wetlands.org/ (accessed 29 November 2022).
