[8] The genus name Aythya is derived from the Ancient Greek word aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle.

[16] The male has a chestnut-coloured head and neck, a black breast and tail, and a pale grey body, marked with fine vermiculations.

While uncommon, individuals are also occasionally seen in the south of England, 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.

[17] These are gregarious birds; they form large flocks in winter, often mixing with other species of diving duck.

[18] Common pochards feed on plant material (including seeds), small fish, molluscs, and other aquatic invertebrates.

They regularly forage in close association with Bewick's and whooper swans, two species that trample underwater sediment to excavate food.

[20] The female builds a platform nest of plant material, with a shallow cup lined with down feathers near its centre.

[21] Like many ducks, common pochards suffer a high rate of parasitic egg-laying, a behaviour also known as egg dumping.

[26] Females sometimes lay their eggs in the nests of other duck species as well; red-crested pochards are unwitting hosts in some areas.

[29] The common pochard is one of the species protected by the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).

In Poland, for example, one studied population showed a 92 per cent decrease in the 30 years after mink first became established in the area.

[32] Birds, including carrion crows and marsh harriers are important nest predators.

These include Paramonostomum aythyae, a trematode which was first isolated from the common pochard; it is carried in the gut.

[35] In some locations, the common pochard may be an important vector of avian schistosomes, which are harboured in the bird's nasal and mesenteric blood vessels.

These schistosomes can be transmitted to humans who work or swim in the same wetland areas as the ducks, potentially causing cercarial dermatitis.