Baer's pochard  (Aythya baeri)

Ducks belonging to the genus Aythya are diving ducks. Baer's pochard has a dark grey to black head, neck and back, with light brownish-red and white sides. The head can be seen to have a dark green sheen on it in sunlight, and at all times the white eyes contrast strongly with the surrounding feathers. A white band on the upper wing can be seen in flight, but not when the wings are folded at rest. Females can be distinguished from males by the greater difference in colour between the head and the brown breast, and also by the more domed head. Juveniles look most similar to females except for a light brown head (2).

Covering quite a range throughout the course of a year, Baer's pochard breeds in eastern Russia, northeastern China and potentially also in Mongolia and North Korea. The majority of the population migrates to spend the winter in eastern and southern China, northeastern India, Bangladesh, Thailand, and Myanmar. However, groups have been seen either on passage or during winter in many other countries, including Mongolia, Japan, North Korea, South Korea, China, Hong Kong, Taiwan, Pakistan, India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Vietnam, and the Philippines (4).

During the breeding season, Baer's pochard prefers areas with a fair amount of vegetation in order to build a secure nest. It inhabits small lakes, larger shallow lakes, as well as fast-flowing rivers and streams, providing there is rich aquatic vegetation. Nests are built amongst thick vegetation, sometimes within gull colonies, but most commonly in reed beds once they have thawed. During migration, Baer's pochard will stop to rest on reservoirs, lakes and rivers. In the winter it selects wetlands such as marshes, paddy fields, and sandy islands within freshwater lakes (4).

An accomplished diver, Baer's pochard can stay submerged for around 40 seconds, reaching a depth of about two metres whilst looking for insects, molluscs, shrimps, fish and algae during the breeding season, and aquatic plants and seeds during migration and the winter season (4).

Males and females form pair bonds shortly after arriving at the breeding grounds from mid April onwards. The first eggs are laid in May, the last in June, until between 9 and 15 are in each nest. The nests are often built close together, and near those of other species as well. Some females will lay their eggs in the nests of the common pochard and the gadwell, but this strategy may be slightly ineffective, as the common pochard, at least, is known to lay her eggs in the nests of Baer's pochards. Incubation lasts between 23 and 28 days – the eggs are warmed by the female alone, but the male will guard her and feed them both. In undisturbed areas the chicks that hatch first will remain close to the nest until all the eggs have hatched, but if disturbance occurs the parents are increasingly likely to abandon the final few eggs to move the successful hatchling away from the area. The ducklings are looked after by both parents for two or three weeks before they learn to dive and forage alone. The adults leave to moult whilst the ducklings form new flocks (4).

Shockingly, surveys have shown that around half of the total wintering wildfowl of the middle and lower basins of the Yangtze River were killed each year by hunters through netting, shooting and poisoning. This indiscriminate loss of birdlife impacts not only on those birds that are already deemed to be under threat, but all other birds in the area. Whilst some Aythya species are not as vulnerable as the Baer's pochard, hunters are usually unable to distinguish between them anyway, and so cannot spare those individuals that may prove to be so important in maintaining a viable population of Baer's pochard. Eggs are also collected from nests, and as well as the obvious drop in reproductive output this causes, the breeding grounds become less suitable as a result of the disturbance, causing other nests to be abandoned (4).

The drainage of wetlands and the removal of large quantities of aquatic vegetation to aid fishing have caused a fall in the water level at breeding grounds. This has a continuing impact on many waterbirds, lowering their reproductive output significantly. Pesticide run-off and removal of vegetation has lead to an unbalanced ecosystem in which weed growth and siltation destroys water quality, ultimately reducing the value of Baer's pochard's habitat (4).

Killing this species is banned in Mongolia, Hong Kong, Myanmar and some provinces in China, but the large-scale hunting methods used and the difficulty in distinguishing Baer's pochard from other duck species, notably from the similar ferruginous duck (Aythya nyroca), make it difficult to enforce the laws. This, and many other waterfowl species, would benefit from a ban on the spring shooting of ducks in Russia, and the creation of more protected areas in addition to those Baer's pochard already uses. The education of hunters as to the identification of threatened species may help, and it is important that Baer's pochard is upgraded to become a nationally protected species in mainland China and is put on Schedule I of the Wildlife Act of India (4).

For further information on the Baer's pochard see:

• BirdLife International. (2001) Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK.

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk