Abstract

Discrimination abilities of Adélie Penguins Pygoscelis adeliae were studied by cross-fostering eggs within two days of laying, chicks within five days of hatching, chicks 11-15 days of age and chicks 17-21 days of age. Our results show that Adélie Penguins have no innate mechanism for recognition of offspring. Discrimination by adults was apparent only after 17-21 days of post-hatching familiarity, which corresponded with the end of the guard stage. By contrast, chicks may have learnt to discriminate adults by 11-15 days of age. During the guard stage, within-brood food allocation by parents was determined by sibling competition.