The grey lag goose, Anser anser, inhabits the calm, still waters of central and northern Europe, is over 3 ft long and weighs nearly 8 lb. It is coloured grey-brown, vermiculated below, with pale forewings visible in flight. These geese are migrants which winter in southern and western Europe and Asia, sometimes also in North Africa.

The female builds the nest and incubates alone; but the male remains close by, as if to keep guard. The nest is generally made of reeds or other aquatic vegetation and may be surrounded by water on all sides. In Scotland these geese nest among heather and rushes on islands or by the shores of lochs (lakes). The 4-6 or more eggs rest on a soft layer of grey down which the goose tears from her belly to line the nest.

The European farmyard geese are descendants of the grey lag. The process of domestication can be traced to the Egyptians as long ago as 2200 B.C. The several breeds are raised chiefly for their meat, fat and feathers, the white form predominating as its feathers have a higher market value.