Cackling Goose - Systematics

Systematics

The Cackling Goose was originally considered to be the same species or a subspecies of the Canada Goose, but in July 2004 the American Ornithologists' Union's (AOU) Committee on Classification and Nomenclature split the two into two species, making Cackling Goose into a full species with the scientific name Branta hutchinsii. The British Ornithologists Union followed suit in June 2005.

The AOU has divided the many associated subspecies between both animals. To the present species were assigned:

• Richardson's Cackling Goose (Branta hutchinsii hutchinsii)
• Aleutian Cackling Goose (Branta hutchinsii leucopareia)
• Small Cackling Goose (Branta hutchinsii minima)
• Taverner's Cackling Goose (Branta hutchinsii taverneri)
• †Bering Cackling Goose (Branta hutchinsii asiatica) - doubtfully distinct from B. h. leucopareia; extinct (c.1929)

The distinctions between the two geese have led to a great deal of confusion and debate among ornithologists. This has been aggravated by the overlap between the small types of Canada Goose and larger types of Cackling Goose. Most interestingly, the old "Lesser Canada Goose" was believed to be a partly hybrid population, with the birds named taverneri considered a mixture of minima, occidentalis and parvipes. In addition, it has been determined that the Barnacle Goose is a derivative of the Cackling Goose lineage, whereas the Hawaiian Goose is an insular representative of the Canada Goose.

A recent proposed revision by Harold Hanson suggests splitting Canada and Cackling Goose into six species and 200 subspecies. The radical nature of this proposal has provoked surprise in some quarters; Richard Banks of the AOU urges caution before any of Hanson's proposals are accepted.

For more information on the subject, see the following:

• Stackhouse, Mark. The New Goose.
• Angus, Wilson. Identification and range of subspecies within the Canada and Cackling Goose Complex (Branta canadensis & B. hutchinsii).
• Moser, Timothy J., Craven, Scott R. and Miller, Brian K. Canada Geese in the Mississippi Flyway: A Guide for Goose Hunters and Goose Watchers.