northern Africa, and western Asia, the original domesticated geese are
derived from the Greylag Goose, Anser anser.
In Eastern Asia, the original domesticated geese are derived
from the Swan Goose Anser cygnoides; these are
now known as Chinese Geese. Both have been widely introduced in more
recent times, and modern flocks in both areas (and elsewhere, such as
Australia and North America) may consist of either species, and/or
hybrids between them. Chinese Geese may be readily distinguished from
European Geese by the large knob at the base of the bill, though
hybrids may exhibit every degree of variation between them.