A close up picture taken of a white goose found along the side of a road in Washington State. True geese are medium to large birds, always associated to a greater or lesser extent with water. Geese have been domesticated for centuries. In the West, farmyard geese are descended from the greylag, but in Asia the swan goose has been farmed for at least as long. All geese eat an exclusively vegetarian diet, and some can become pests when flocks feed on arable crops. Geese tend to lay a smaller number of eggs than ducks. However, both parents protect the nest and young, which usually results in a higher survival rate for the young geese, known as goslings.