Goose barnacle migrate, it was thought that barnacle geese, "Branta leucopsis", developed from this crustacean, since they were never seen to nest in temperate Europe, hence the English names "goose barnacle", "barnacle goose" and the scientific name "Lepas anserifera" (, "goose"). The confusion was prompted by the similarities in colour and shape. Because they were often found on driftwood, it was assumed that the barnacles were attached to branches before they fell in the water. The archdeacon of Brecon, Gerald of Wales, made this claim in his "Topographia Hiberniae". Since barnacle geese were thought to be "neither flesh, nor born of flesh",
Canada goose and Nomenclature split them into two species, making the 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 subspecies between the two species. The subspecies of the Canada goose were listed as: The distinctions between the two geese have led to 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 population, with the birds