Common Pochard Aythya ferina 紅頭潛鴨
Category I. Scarce winter visitor.
IDENTIFICATION
Dec. 2014, Michelle and Peter Wong. Male (left), female (right).
42-49 cm. Sturdy duck with distinctive domed crown and smooth junction between bill and head; broad indistinct pale wing bars covering most flight feathers visible in flight, when it also shows a large head and short tail.
Adult male breeding (left) has reddish eyes, orange-brown head, broad paler greyish band across dark bill, black chest and stern and pale grey vermiculated upperparts and flanks.
Female (right) is somewhat variable, though generally rather plain. Upperparts brown to washed out greyish-brown with indistinct darker vermiculations. Head may be unmarked but paler on fore part of the face, or it may have a paler line behind eye, pale lores, cheeks and throat, and often a large paler spot at base of bill. Pale band behind bill tip is narrow.
Dec. 2012, Michelle and Peter Wong. First-year male.
First-year birds are browner overall. Males in their first-winter increasingly differ from females as they acquire adult-type mantle, scapular and flanks feathers, a broader pale subterminal bill band and reddish tone to the head.
VOCALISATIONS
The male is generally only vocal during courtship or on the breeding grounds. The call of the female, often given in flight, is a rolling throaty sound.
DISTRIBUTION & HABITAT PREFERENCE
The majority of records have occurred in freshwater or brackish ponds at Mai Po NR, and all have been in the Deep Bay area from Tsim Bei Tsui to Lo Wu, or on the Kam Tin River. It is rare in intertidal areas.
OCCURRENCE
Not recorded in Hong Kong prior to 1970, Common Pochard is now known to be a scarce winter visitor to Deep Bay. Carey et al. (2001) regarded its main period of occurrence as being the second week of November to the end of March; however, this century it has occurred from the first week of November to the third week of February, with only one March record, on the 9th. As Figure 1 indicates, its occurrence is somewhat erratic, and it appears to have become less regular this century compared with the 1990s.
Over-summering birds were recorded in 1970 and 2018, and a male was present on 28 May 1990. Excluding these, extreme dates are 22 October 1995 and 1999 and 19 April 1990. The highest count is 19 during 5-6 December 2014.
A presumed hybrid with Ferruginous Duck was present from 14 December 2017 to 5 March 2018.
BEHAVIOUR, DIET & FORAGING
No observations.
RANGE & SYSTEMATICS
Monotypic. Breeds between approximately 40oN and 60oN from eastern Europe and southern Scandinavia east through Russia, Kazakhstan and Mongolia to northeast China. Winters from western Europe south to north and east Africa, and east to northern parts of the Indian subcontinent, northern Indochina, south China, east Asia and northern Philippines. In China breeds in the northwest and northeast, and winters south from the Yangtze (Liu and Chen 2020).
CONSERVATION STATUS
IUCN: VULNERABLE. Population trend decreasing rapidly across much of its range.
Figure 1.
Carboneras, C., G. M. Kirwan, and C. J. Sharpe (2020). Common Pochard (Aythya ferina), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.compoc.01
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.
