Diving depths of the Chinstrap Penguin Pygoscelis antarctica

Diving depths of four breeding chinstrap penguins were recorded throughout complete foraging trips to sea lasting 18-48 h at Signy Island, South Orkney Islands. Deeper dives reached 70 m but 90% of dives were shallower than 45 m and 40% were to less than 10 m. The diving pattern is compared with those of king penguins and Antarctic fur seals. Chinstrap penguins feed on krill and it is suggested that they do so chiefly during shallow dives at night when krill are near the surface. Using data on average measurements and weight of krill taken by chinstraps at Signy Island, and estimates of at-sea metabolic rate and the size of meals delivered to their chicks by the study birds, it is calculated that about 16 krill are caught per dive of duration c. 1.6 min.