The Greylag Goose (also spelled Graylag in the United States), Anser anser, is a bird with a wide range in the Old World. It is the type species of the genus Anser. 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. The Greylag Goose is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. The Greylag is a large goose, 74–84 cm (29–33 in) long with a 149–168 cm (59–66 in) wingspan and a body weight of 2.3–5.5 kg (5–12 lbs). It has a large head and almost triangular bill. The legs are pink, and the bird is easily identified in flight by the pale leading edge to the wing. It has a loud cackling call, kiYAAA-ga-ga, like the domestic goose. The western European nominate subspecies, A. a. anser, has an orange-pink bill and is slightly smaller and darker than the pink-billed Asian race, A. a. rubrirostris. Eastern European birds are often intermediate in appearance.