Baer's Pochard Aythya baeri 青頭潛鴨
Category I. Very rare winter visitor occurring less than annually; not recorded since 2013. Much declined.
IDENTIFICATION
Feb. 2012, Michelle and Peter Wong. Female.
41-47 cm. Female has blackish-brown head with paler more chestnut loral patch, brown chest and brown and white flanks and dark irides; white undertail coverts less obvious than male. Bill dark grey, paler near tip with black nail.
Feb. 2012, Michelle and Peter Wong. Female.
In flight all birds show an obvious broad white wing bar and pale underwings. The wing bar fades on the outer primaries more than it does on Ferruginous Duck.
Adult male breeding has white or pale yellow irides, dark green-glossed head and neck, deep orange-brown chest, chestnut and white flanks and white undertail coverts.
VOCALISATIONS
Non-breeding season vocalisations unknown.
DISTRIBUTION & HABITAT PREFERENCE
All records are from the Deep Bay area, primarily Mai Po; most have occurred from Tsim Bei Tsui to Lok Ma Chau, but there is one record from the fish pond area of Hoo Hok Wai.
OCCURRENCE
Although the first report was of a young male shot out of three seen on 19 February 1972 (Webster and Viney 1973), the first substantiated record occurred on 30 November 1975 (Viney 1976). Baer’s Pochard was initially infrequently recorded probably due to a lack of familiarity with its identification features; however, it proved to be a scarce winter visitor to Deep Bay.
Carey et al. (2001) stated that Baer’s Pochard was mainly recorded between the second week of November and the middle of March; however, since 1999 most records have occurred from 4 December to 11 March (Figure 1). Earlier records comprise single females present during 16-30 August 2003 and 14-22 October 2000, while the latest in spring occurred on 25 April 1990.
Peak numbers previously occurred during the middle two weeks of January, including the maximum count of 30 on 10 January 1987. Generally, however, most records have been of one to four birds. Since the winter of 1987-88 there has been a decline in numbers recorded (Figure 2), and it has only been recorded in five winter periods this century. The most recent record occurred on 21 December 2013.
BEHAVIOUR, FORAGING & DIET
No observations.
RANGE & SYSTEMATICS
Monotypic. Originally bred in northeast China and adjacent parts of Russia, and spent the non-breeding season in south China, northern Indochina and northeast areas of the Indian subcontinent (Carboneras and Kirwan 2020); however, these ranges have considerably contracted, and it seems that few now winter outside China (BirdLife International 2021). In China it breeds from the northeast as far south as the Yangtze floodplain and winters in scattered areas south of the Yellow River (Liu and Chen 2020).
CONSERVATION STATUS
IUCN: CRITICALLY ENDANGERED. Population estimated at 150-700 mature individuals. Apparently undergoing an extremely rapid population decline due to wetland destruction and over-harvesting of birds and eggs.
Figure 1.
Figure 2.
BirdLife International (2021) Species factsheet: Aythya baeri. Downloaded from http://www.birdlife.org on 17/09/2021.
Carboneras, C. and G. M. Kirwan (2020). Baer's Pochard (Aythya baeri), 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.baepoc1.01
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.
Viney, C. A. (1976). Report on the birds 1975. Hong Kong Bird Report 1975: 5-38.
Webster, M. and C. A. Viney (1973). Report on the birds 1972. Hong Kong Bird Report 1972: 4-42.
