Common pochard and small populations are sometimes observed on the River Thames. Large numbers stay overwinter in Great Britain, after the birds retreat from Russia and Scandinavia. These are gregarious birds, forming large flocks in winter, often mixed with other diving ducks such as the tufted duck, with which they are known to hybridise. These birds feed mainly by diving or dabbling. They eat aquatic plants with some molluscs, aquatic insects and small fish. They often feed at night, and will up-end for food as well as the more characteristic diving. In number of countries the population of Common Pochard is decreasing
Baer's pochard found just 131 individuals on Liangzihu Lake, and only another three flocks of ten, eight, and three individuals at other sites. Hunting and wetland destruction are thought to be the causes of the decline; unconfirmed reports from eastern China suggest that as many as 3,000 individuals may be hunted every year. Baer's pochard breeds around lakes with rich aquatic vegetation, nesting in dense grass, flooded tussock meadows, or flooded shrubby meadows. In Liaoning, China, it is normally found in densely vegetated coastal wetlands, or around lakes and ponds surrounded by forest. In winter, it occurs on freshwater lakes and reservoirs.