Sugarmouse Island is an islet

Islet

An islet is a very small island.- Types :As suggested by its origin as islette, an Old French diminutive of "isle", use of the term implies small size, but little attention is given to drawing an upper limit on its applicability....

 with an area of 0.54 ha

Hectare

The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...

 in south-eastern Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It is part of the Mutton Bird Island Group, lying close to the southern end of the south-western coast of Tasmania

Tasmania

Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

. The island is part of the Port Davey Islands Important Bird Area

Port Davey Islands Important Bird Area

The Port Davey Islands Important Bird Area comprises over 20 small, rocky islands scattered both within, and in the vicinity of, the mouth of Port Davey, an inlet on the south-west coast of Tasmania, Australia...

, so identified by BirdLife International

BirdLife International

BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...

 because of its importance for breeding seabirds.

Fauna

Recorded breeding seabird

Seabird

Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...

 species are the Fairy Prion

Fairy Prion

The Fairy Prion is a small seabird with the standard prion plumage of black upperparts and white underneath with an "M" wing marking.-Taxonomy:...

 (2000 pairs) and Black-faced Cormorant

Black-faced Cormorant

The Black-faced Cormorant , also known as the Black-faced Shag, is a medium-sized member of the cormorant family. Upperparts, including facial skin and bill, are black, with white underparts. It is endemic to coastal regions of southern Australia.-Ecology:The Black-faced-Cormorant feeds largely on...

.