In the wild, Humboldts spend most of their lives in the ocean, only coming ashore to moult and to breed. The annual moult is catastrophic - the birds lose all their feathers before growing completely new plumage. Immediately prior to the moult the penguins gorge themselves on fish, instinctively knowing they are about to lose their waterproof covering for a few days. After gorging, the penguins swell up - including their flippers - at the Park this results in the keepers needing to cut off their ID tags to allow for expansion, before replacing them once the swelling has returned to normal. The photo on the left, taken this week at the Park shows an adult Humboldt penguin in moult - looking swollen and quite shabby!