American Wigeon Mareca americana 綠眉鴨
Category I. Accidental.
IDENTIFICATION
Feb. 2016, Michelle and Peter Wong. Male.
45-58 cm. Identifying adult males is straightforward due to the white forehead and crown, broad greenish stripe from eye back to the nape and pinkish tinged breast and flanks.
Feb. 2016, Michelle and Peter Wong. Male.
On both sexes the axillaries and median underwing coverts are white (occasionally some birds have faint greyish marks and shaft streaks) and, compared to Eurasian Wigeon, a slightly larger head with a steeper forehead.
The female utters a throaty croak.
DISTRIBUTION & HABITAT PREFERENCE
Both records are of birds associating with Eurasian Wigeons and were recorded at Mai Po, on the intertidal mudflats or on ponds in the Nature Reserve.
OCCURRENCE
There are two records of males:
2016: one seen mainly from Mai Po NR boardwalk from 10 January to 29 February (Wong and Wong 2018).
2018: one at Mai Po NR during 7-24 February.
Hybrid American x Eurasian Wigeon
The main issue in regard to identifying American Wigeon in the region is determining the extent to which hybrid influence can be ruled out. Most birds identified as hybrids in HK have had varying amounts of rufous on the head.
In 1992 the first hybrid Eurasian x American Wigeon, a male, was seen (Carey 1993). Since then, hybrid males have been recorded in about 50% of winter periods, mostly singles, though three were seen on one occasion. Extreme dates are 22 October to 3 April. It is presumed likely that females also occur though are not found due to the difficulty of identification.
BEHAVIOUR, FORAGING & DIET
No observations.
RANGE & SYSTEMATICS
Monotypic. Breeds largely from the Aleutians through Alaska to much of western Canada, with low-density and scattered populations in the east and northern U.S.A.; winters along the Pacific coast of Canada through much of western U.S.A., along the western coast down to Florida and the Caribbean south to extreme northern South America (Mini et al. 2020). In China has been recorded in Beijing, Jiangsu, HK and Taiwan (Liu and Chen 2020).
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Carey, G. J. (1993). Hybrid male wigeon in East Asia. Hong Kong Bird Report 1992: 160-166.
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.
Mini, A. E., E. R. Harrington, E. Rucker, B. D. Dugger, and T. B. Mowbray (2020). American Wigeon (Mareca americana), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.amewig.01
Wong, M. and P. Wong (2018). American Wigeon Anas americana at Mai Po Nature Reserve. The first Hong Kong record. Hong Kong Bird Report 2016: 228-230.
