Brant (goose) the "Agreement on the Conservation of African-Eurasian Migratory Waterbirds" applies. "Branta" is a Latinised form of Old Norse "brandgás", "burnt (black) goose", and "bernicla" is the medieval Latin name for the barnacle. The brant and the similar barnacle goose were previously considered one species, formerly believed to be the same creature as the crustacean. That myth can be dated back to at least the 12th century. Gerald of Wales claimed to have seen these birds hanging down from pieces of timber, William Turner accepted the theory, and John Gerard claimed to have seen the birds emerging from their shells. The
Chen (genus) recognizes this genus as distinct; most other authorities today consider it a subgenus of "Anser". Like grey but unlike the "Branta" black geese, their feet and legs are colored in reddish hues. The bill is also reddish in these birds as in most grey geese, except in adult males of Ross's goose which have a blue-black grainy cere. The wingtips are black, as in all true geese, whereas the head is always white without any markings or pattern in adult birds of this genus, which distinguishes them from all other true geese except feral domesticated geese. The rest of the