AbstractIt is interesting to note that all of the world's wild geese are native to the northern hemisphere. Although Canada geese from North America have been introduced into Australia and New Zealand, they are not native to that area. A number of goose-like birds are found in Africa and Australia. These birds are substantially different from true geese and are classified differently. South America is home to a large group known as sheldgeese. These birds might best be described as modified ducks which, as a result of evolutionary change, have assumed goose-like characteristics. As an example, they have adapted to a terrestrial existence and, like true geese, have become grazing animals. As a result, their legs have lengthened and moved forward to accommodate their adaptation to land areas. Their beaks have become more goose-like - again, to better adapt to grazing. The general appearance is much more like that of geese than ducks. However, there is one major difference that still links them with the ducks. Unlike the true geese, in which the sexes are identical (known as monomorphism), the sheldgeese are dimorphic and males and females are much different in outward appearance.
The geese of the northern hemisphere are divided into two groups: those that are known as brent geese or brant, and those referred to as true geese. Differences between the two groups are slight. Members of the brant family have black feet and bills, whereas true geese have colored feet and bills. Brent geese also have considerable black in the overall plumage, which is not seen in true geese. Despite these differences, and the fact that hybrids between the two forms are sterile, the two groups are very close to each other. True Geese
Throughout the northern hemisphere are nine species of true geese. They are the Bean geese, Greylag geese, White-fronted geese, Snow geese, the Bar-headed Goose, Pinkfooted Goose, Swan Goose, Ross's Goose and the Emperor Goose. The true geese are classified in the genus Anser, from the Latin, meaning goose. Members of the brant family are in the
genus Branta, from the Greek Bren- ---------------thos, also meaning goose.
The Bean goose, which is widely distributed throughout Europe and Asia, is represented by five well defined sub-species. They range in size from the comparatively small Russian Bean Goose to the large Middendorf s Bean Goose - a little known form found in remote areas of central China. Bean geese were so named because they frequently feed in bean fields, a food source not usually favored by other species of geese. Aside from the two species listed above, three other races exist - the Wes tern Bean Goose (also known as the Yellow-billed Bean Goose), the Thick-billed Bean Goose, and Johannson's Bean Goose. All Bean geese are similar in appearance. The head and neck are a rich brown, bodies are brownish gray, feet are bright orange, and bills are black with yellow markings.
The Swan Goose of China is unique.
Its name is derived from the fact it has a very long black bill, much like that seen in the northern swans. It is the only member of the true goose family with a totally black bill. The plumage color is tawny buff and the feet are orange. It is native to remote areas of central China, and little is known of its current status. It is generally believed, however, that it exists in comparatively low numbers. Interestingly, the Swan Goose was domesticated in China - probably long before the Greylag was domesticated in Europe. The white and brown Chinese, and the gray African are the three domestic forms that have evolved. The Brown Chinese is very similar in plumage to the Swan Goose, but is quite different in shape.
One of the more interesting groups is that made up of the various Whitefronted geese. Their distribution is widespread, extending across most of North America, Europe and Asia. As is true with Bean geese, different subspecies vary in size. Basic plumage color varies from gray/brown in some races to rich brown in others. Feet and legs are orange and bills pinkish. At the base of the bill, on the fore part of the face, is a ring of white feathers, hence the name "White-front".