Warham J. (1972) Aspects of the biology of the Erect-crested Penguin Eudyptes sclateri. ARDEA 60 (3-4): 145-184

1. Observations made at Antipodes Island during the 1968/69 breeding season of the Erect-crested Penguin Eudyptes sclateri, are presented together with a summary of previous information concerning the morphology, breeding and behaviour of this species. The observations formed part of a wider project to embrace all members of the genus. 2. The breeding timetable has been deduced from past and present records. The birds are believed to return to Antipodes Island in the second week of September and to begin laying about 3 weeks later, with a peak of laying about 12 October. Two eggs, the first smaller than the second, comprise the clutch. Incubation is probably undertaken by both sexes and is thought to last for about 35 days. The chicks are tended by both parents, huddle in crFches when strong enough to leave their nests, and are fed by both parents, but particularly by the female, and probably about once daily. Peak of departure for the chicks is about 30 January whereupon the breeders leave to gain weight at sea in preparation for their annual moult. 3. Breeding birds start to return to moult about the third week of February and re-occupy their nesting sites, the males tending to appear before the females. Most pairs are re-united by 9 March and 50% of them are in moult by 11 March. From 24-30 days elapses between a bird's arrival and its departure to sea where the winter months are spent. Few still remain ashore after 21 April. 4. Non-breeding birds come ashore increasingly during the period when the chicks are no longer guarded. Non-breeders moult before the breeders and leave the island as the breeders start to arrive. The non-breeders appear to lose about 50% of their initial weight during their moult. Yearlings also moult before the breeders. 5. The extent of the sexual dimorphism was examined by measuring the bills, flippers and body weights of samples of live birds. The data are tabulated for comparison of breeding adults, yearlings and well-feathered chicks. The dimorphism appears to extend to all three classes but is most pronounced in the adults where the males are about 17% heavier than the females and have bills 11-16% longer, deeper and wider. 6. Erect-crested Penguins use elaborate forms of display on their breeding grounds and 20 distinct patterns are described in this paper. In general these are similar to, and probably homologous with, the postures of the better known Rockhopper Penguin E. chrysocome.