The breeding male is a diving duck with a striking reddish-brown head.
In breeding plumage, the male has a reddish-brown head, black breast and gray back. The female is brown, with a paler face and throat.
Common pochards can favour small mussels. When captive birds were offered freshwater mussels of varied sizes, they selected especially small ones. A large bill did not simply correspond to a preference for large prey: the mussel sizes chosen differed from those predicted using energy content and the time needed to swallow them.
The 1987 paper reported a series completed by two male pochards and one female. Birds were given a week to become accustomed to mussels and were tested individually. Mussels were spaced out on a stony edge beside the water. When ten size classes were offered, the birds took mussels up to 15 millimetres long and favoured the smallest. A separate two-size experiment found that pochards could discriminate even small length differences between larger mussels. These observations documented selection among prey laid out within view.
An extinction-risk assessment has not been added yet.
In common pochard breeding areas centred on Russia, changes in fishpond management and excessive nutrient enrichment of lakes have been identified as possible drivers of habitat deterioration. Connecting breeding and wintering areas can help target protection of wetlands providing food and nesting cover. In 2020, authors assessing breeding areas centred on Russia proposed analysing winter waterbird counts, including those from Japan and Korea, alongside metal-ring recoveries. Linking breeding origins and winter destinations could help identify sites to safeguard along migration routes. They also called for investigating factors affecting breeding success and abundance at individual wetlands so that management can address local conditions.