Constant observations of an adelie penguin (Pygoscelis adeliae) colony to determine the precise time of nest relief, the duration of foraging trips and the rhythms of behaviour and the levels of hormones in their blood

The precise time of nest relief, the duration of foraging trips and the rhythms of behaviour were measured by keeping a colony of Adelie penguins under constant observation throughout the breeding season at the Cape Bird colony. The study colony was mapped and all birds in the colony were banded. The colony was under constant supervision throughout the breeding period. To establish whether the complementary nature of foraging trips observed in successful pairs could be accounted for by the duration of the pair bond and experience, daily observations were made on the banded birds in the study colony from the 84/85 season. The level of hormones in the blood of Adelie penguins was determined throughout an entire breeding season. Samples were centrifuged on site and hormone levels assessed.