Marion Island is a small (290 square km), isolated volcanic island in the "Roaring Forties" in the Southern Ocean. It is the larger of two islands that make up the Prince Edward Islands. The island has a low mean annual air temperature (c. 5.7 °C), high humidity (83%) and an annual precipitation of approximately 1900 mm. The island is characterized by a high degree of cloudiness and strong, predominantly westerly winds which reach gale force proportions for much of the year.

The Prince Edward Islands (PEI) are remote and inhospitable, however they represent a valuable resource. The PEI not only support many rare species but they also provide a valuable breeding ground for many bird and mammal species.