Mallard duck (© Philippe Paternolli/Getty Images)

At daybreak, the mallard glides over the still water like a brush across a canvas. Its shimmering plumage—emerald-green head in the male, speckled brown coat in the female—catches the first light. It can be seen from the marshes of the Camargue to the urban canals of Amsterdam, a faithful companion of Europe's aquatic landscapes.