Sea ice

At the beginning of the breeding season the Antarctic sea-ice extends to approximately nine hundred kilometres offshore of the Mawson coast. As summer progresses and temperatures warm, the sea-ice melts and gradually retreats into the Antarctic coast. By February, the sea-ice has usually all gone and seawater laps the shores of Béchervaise Island.

The summer sea-ice retreat facilitates chick rearing as it allows easy penguin access from their breeding grounds (inshore islands) to their feeding grounds (open water). Extensive sea-ice cover during incubation (Nov - mid Dec) means the penguins must travel long distances to reach the water. The retraction into the Antarctic coast, over the summer, assists the adults in providing frequent meals to their chicks and allows fledglings to enter the water easily late in the breeding season. Minimal energy expenditure at this time is important for the fledglings, as they must learn both how to swim and how to catch their first independent meal.