Baer's Pochard

The Baer's pochard is 41–47 cm (16–19 in) long with a 70–79 cm (28–31 in) wingspan. The male is slightly larger, weighing on average 500–730 g (18–26 oz), wings lengthed 18.6–20.3 cm (7.3–8.0 in), tail at 53–60 mm (2.1–2.4 in), and culmen at 38–44 mm (1.5–1.7 in). Relatively, the female weighing on average 590–655 g (20.8–23.1 oz), wings lengthed 19.1–20.5 cm (7.5–8.1 in), tail at 51–64 mm (2.0–2.5 in), and culmen at 40–44 mm (1.6–1.7 in). Both male and female's tarsometatarsus lengthed 33–34.7 mm (1.30–1.37 in). Breeding male has a black head and neck with green gloss, white or paler yellow eyes, blackish-brown back, dark chestnut breast, white or light chestnut flanks and a short and low tail. While it is likely to look completely black in poor light. Female has brown eyes and a dark brown head and neck that blend into the chestnut-brown breast and flanks. Eclipse and first-winter male resembles female, but retain the white eyes. Both male and female have wide white speculum feathers, white vent-side, dark-grey bill, black nail and dark-grey tarsometatarsus. It is similar to its close relative, the ferruginous duck (A. nyroca), both have white vent-side and iris in males, black nail, and wide white speculum feathers. Although Baer's pochard is bigger, has a longer head, body and bill. …

Baer's pochard traditionally bred in the Amur and Ussuri basins in Northeast China and the southeastern Russian Far East. In recent years, it has also colonised North China and Central China. It winters in most areas south of the Yellow River in China, Taiwan, Japan, Bangladesh, India, North Korea, Laos, Myanmar, Nepal, Thailand and Vietnam, and occasionally appears in Bhutan, South Korea, Philippines or Pakistan as a rare vagrant. It leaves its wintering grounds by mid-March and returns to them by mid-October or early November. The species has become extremely rare in its traditional breeding areas, and since 2010, there have been no confirmed breeding reports in all sites north of Beijing. However, the numbers recorded during the breeding season are smaller than those recorded in winter, so there may still be unknown breeding sites. For example, there are some doubtful breeding reports in the Chinese part of Lake Khanka, the Russian part of Lake Khasan, and the Muraviovka Park. Since 2012, new breeding sites have been discovered in several provinces of China, including Hebei, Hubei and Jiangxi; the latter two cities are far from traditional breeding sites in the Amur and Ussuri basins. …

Baer's pochard is a shy species, that inhabit open, slow-flowing lakes, swamps and ponds. It breeds around lakes with rich aquatic vegetation, nesting in dense grass, flooded tussock meadows, or flooded shrubby meadows. In winter, it forms large flocks on large and open freshwater lakes and reservoirs with other pochards. It has strong wings, and can flyor walk at high speeds. It is also good at diving and swimming, and can quickly take off from the water when threatened or disturbed. In migrating season, they form small groups of more than 10 or dozens of birds, flying at low altitudes in wedge-shaped formations. During winter, Baer's pochard sleeps during the day, leaves for unknown feeding sites with other ducks in the dusk, and returns before dawn. Little is known about their diet beyond aquatic plants, grass seeds and molluscs.

Breeding. Baer's pochard appears to have a monogamous mating system, at least within a breeding season. In traditional breeding grounds in northeastern China, Baer's pochard gathers in gaps in the ice before it completely thawed. After the ice season, it gathers on the large, open lakes. They breed from mid-to-late May. While in Fuhe Wetland in Wuhan, Hubei, Baer's pochard gathers in large groups on the open lakes before breeding season. It is divided into small groups in mid-April, in which they will courting and mating. …