The Magellan or Upland Goose is not a true goose but a Sheldgoose or Shelduck.
There are two subspecies, the Lesser Magellan
(c. p. picta) from Argentina/Chile, shown here, and the Greater Magellan
(c. p. leucoptera) from the Falklands and south Atlantic.
The male Magellan Goose is white with black markings (top row) while the female (above) is mainly a ruddy orange colour with close black banding from the neck down.
Male Lesser Magellans from the north of their range have a white breast/belly and from the south they are closely banded from the neck like the female but black & white.
Intermediate range Lesser Magellan males show part white breasted, part banding, as below left. Females always have close banding.
Male and female Magellan/Upland Geese also make different sounds: like some humans, the males whistle and the females cackle.