Each September, male Magellanic penguins return to Magdalena Island to reclaim the burrow they used the year before. After they spend time repairing the nest, their female mates travel to the island to begin the breeding season. This extends through late February or early March when the mature chicks swim away. Then the adults molt for two to four weeks. They do not enter the water during this period so they must fast. When their plumage has regrown in April, they begin their northerly migration.