Moult in adult Royal Penguins, Eudyptes schlegel

Mass change during moult was measured in Royal Penguins at Macquarie Island during 1995, in order to estimate the energetic costs and prey-consumption rates required to fuel the moult. Masses of 30 birds were taken during each of the following stages: upon their return from the pre-moult foraging trips; in the middle of the moult; and at the completion of moulting. During the 36-day pre-moult foraging trip individuals increased in mass by 3 kg, accumulating 83.3 g day-1. The moult lasted 28 days and 99% of birds moulted at their breeding sites. During moult birds lost 46-47% of their pre-moult mass, with males expending an estimated 57997 kJ and females 57229 kJ during this period. It was estimated that 1.39 × 107 kg of food are required to fuel this stage in the life cycle of Royal Penguins at Macquarie Island, which therefore constitutes an important component of their overall energy budget.