 The final phase was subaerial basalt lava flows on top of the previous volcanic deposits after the lake drained or boiled away.The island has been identified as an Important Bird Area (IBA) by BirdLife International because it supports a breeding colony of about 800 pairs of imperial shags.Although a large colony of Adélie penguins and snow petrel nests were reported from the island in 1901, it is not known whether they continue to breed there.