What is "common shelduck"

n. A waterfowl species shelduck, ''Tadorna tadorna''.

The common shelduck (Tadorna tadorna) is a waterfowl species shelduck genus Tadorna. It is widespread and common in Eurasia, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb. Its scientific name comes from the French name Tadorne for this species. It may originally derive from Celtic roots meaning "pied waterfowl", essentially the same as the English "shelduck".

Fossil bones from Dorkovo ( Bulgaria) described as Balcanas pliocaenica may actually belong to this species. More likely, they are an extinct species of Tadorna (if not a distinct genus) due to their Early Pliocene age; the present species is not unequivocally attested from the fossil record until some 2–3 million years later ( Late Pliocene/ Early Pleistocene).