The Greylag Goose (Anser anser), aka Graylag in the US, is a bird with a wide range in the Old World. It was in pre-Linnean times known as the Wild Goose (Anser ferus). This species is the ancestor of domesticated geese in Europe and North America. Flocks of feral birds derived from domesticated birds are widespread. Reference: http://en.wikipedia.org/wiki/Graylag_Goose