short green grasses. However, recent land use changes towards crop fields and managed pastures have forced them to adapt to and colonize such modern landscapes. Distribution Upland geese occupy the southern South American Continent (southern and central Chile and Argentina) and the Falkland Islands, with a continental distribution ranging from central Chile/southern Argentina to Tierra del Fuego, near Antarctica. Lesser Magellan geese usually reside in Patagonia or southern Chile and migrate north during the winter towards central Argentina, to their wintering grounds. Southernmost populations are more likely to migrate, with migrants reaching flight speeds of over 40 km/h. In 2013, researchers identified a lesser Magellan goose in southern Brazil, redefining the northern edge of their wintering grounds. Greater Magellan geese, however, do not migrate and rarely leave the Falkland Islands. In general, population densities are highest around ponds and in green grasslands. Computer modelling of population ranges suggests that their distribution is favoured by the ample presence of green grasses to feed and breed in, and hindered by human presence, notably urbanization and oil extraction. There is also a sizeable introduced population on the sub-Antarctic South Georgia Island. Behaviour and ecology Breeding Upland goose breed in southern Patagonia or their native islands during the austral summer. They are monogamous, although divorce can occur, and generally return to breed in the same territory every year. After approximately two years from birth, females can start to lay eggs, and usually do so near their birthplace. Males begin breeding later and tend to settle farther away from where they were born. This sexual difference in dispersal distances causes the sex ratio of young to become biased towards the dispersing sex due to the inherent resource constraints of crowding. Therefore, upland geese tend to display a male-biased sex ratio. They breed non-colonially in densely-vegetated areas, generally in September and October on the mainland, and in November on the Falkland Islands. A large population of this species breeds in the New Island Nature Reserve, which was created in collaboration with Falkland Conservation. Males attract females through a courtship display in which they whistle loudly, to which the female responds with softer cackles. As they are monogamous and territorial, a violent fight may break out if a male encroaches on another's territory. Males have been found injured or dead after these fights. The simple nest is either on the ground or within 1.5 m of it,