Barnacle goose were of the same nature as other birds. The question of the nature of barnacle geese also came up as a matter of Jewish dietary law in the Halakha, and Rabbeinu Tam (1100–71) determined that they were kosher (even if born of trees) and should be slaughtered following the normal prescriptions for birds. The mythical barnacle tree, believed in the Middle Ages to have barnacles that opened to reveal geese, may have a similar origin to the other legends already mentioned. Barnacle goose The barnacle goose ("Branta leucopsis") belongs to the genus "Branta" of black geese, which contains species with
Cackling goose 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: 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. The old "lesser Canada geese" were believed to be a partly hybrid