Most of the land is exposed sandstone, after the guano has been exploited in the 20th century.

Landing can be extremely difficult, with heavy swells sweeping round the island even during the calmest sea conditions.

The terrestrial vegetation on the island is limited because of the high number of seabirds.

The island is almost treeless and is covered by grasses and other low-growing plants.

It has been identified as an Important Bird Area (IBA) by BirdLife International because it supports a breeding population of 430,000 pairs of sooty terns, and a large number of boobies.