The Cape Barren goose is a large bird with small head and a short beak. The beak is obscured by a lime-yellow cere, surrounding the large nares of the bird. The Cape Barren goose is grey with black beak. The tail with both of its sets is black. The upper-parts and the under-parts are grey with pale coloring of brown. The forehead and crown are lighter in color, which is more visible in adult geese, while the iris is honey colored. Feathers on its breast and back have paler margins, which give the goose scaly appearance. Their legs are deep pink and feet are black, due to which the bird looks like it has been walking in mud. Feathers on the upper side of each wing have dark grey markings at the tips, which take shape of three small markings, when the bird closes its wings. Young are covered with black and white markings, having black facial mask.
The major area of their distribution is offshore islands near South Australia and Tasmania. At the breeding season, the Cape Barren geese are usually found in grassy areas, tussock grass or bushes. During the rest of the year, they can be seen on beaches, coastal pastures, in brackish lagoons and along the shores of freshwater lakes.
The Cape Barren geese are diurnal birds, spending most of the day grazing. These birds can drink salty and brackish water, due to which the Cape Barren geese are able to live on separated offshore islands throughout the year. The Cape Barren geese don’t tend to swim and will enter the water only in order to protect their chicks. At the breeding season, these birds congregate into loosely organized colonies, where nests are at a distance from each other. The pair fiercely defends its nesting site against any intruders: foxes, dogs, humans and other geese. When threatened, the goose starts lifting its folded wings again and again while stretching out and pumping its neck, and speeds up the movements as the level of aggression increases. The Cape Barren geese attack, either rushing forward and keeping their head low and stretched out or running upright with spread wings. Usually, during the mating season, mated pair of Cape Barren geese imitates these movements, performing them as a "triumph ceremony".
This bird is herbivorous, eating only plant matter. The usual diet of Cape Barren geese includes tussock grass Poa poifornis, which is a common plant on the islands of their habitat. In addition, these birds consume wide variety of grass species, leaves, seeds and stems.
They are monogamous, mating for life. The mated pair establishes and strongly defends its territory. Cape Barren geese breed during winter months, from They are monogamous, mating for life. The mated pair establishes and strongly defends its territory. The Cape Barren geese breed during winter months, from May to June. Usually, the male builds the nest with vegetation on the ground after which the female lays 3-6 eggs, that are creamy-white in color. Then the female incubates the eggs for 34-37 days. Both parents care for the hatchlings and protect them. Around 70-76 days after hatching, the chicks fledge. The youngsters then congregate into small groups, reaching nearby islands or even the continent.. Usually, the male builds the nest with vegetation on the ground after which the female lays 3-6 eggs, that are creamy-white in color. Then the female incubates the eggs for 34-37 days. Both parents care for the hatchlings and protect them. Around 70-76 days after hatching, the chicks fledge. The youngsters then congregate into small groups, reaching nearby islands or even the continent.
Although nowadays the species is not endangered, in the 20th century it has been heavily hunted, which nearly led to its complete extinction. Currently, the population of the Cape Barren goose has highly increased and it's protected by a number of wildlife agencies. However, threats are still present: a part of their breeding grounds can turn into agricultural lands, thus reducing the habitat of this species. It is necessary for these islands to have the status of nature reserves with limited grazing allowed, in order to avoid dense scrubland.
The global population of these birds is considered to be stable and not endangered. The total number of Cape Barren goose population is about 16.000-18.000 birds, approximately 11.000-12.000 of which are mature individuals. In the IUCN Red List, the species is classified as Least Concern (LC).
These birds play important role in the ecosystem of their habitat. They feed upon various plant species, thus dispersing seeds. Also, the Cape Barren goose is a prey species for a number of predators such as owls, foxes, snapping turtles and raccoons.