These are not really geese, but "sheldgeese" more closely related to shelducks than to true geese. This species was the most common by far on our shore excursions in southern South America. The females have dark heads while the males have white heads. Mainland males are polymorphic, some having barred breasts and others have white breasts. Two subspecies are recognized. This is the widespread nominate form from the mainland. A larger race (possibly a cryptic species) where the males are always white breasted is confined to the Falkland Islands.
Nikon P510 Point-and-shoot.