Do Adélie penguins modify their foraging behaviour in pursuit of different prey?

Abstract.

We examined the question, does foraging behaviour of Adélie penguins, Pygoscelis adeliae, change in accord with the prey captured? To provide an answer, we attached instruments that record foraging behaviour to free-ranging Adélie penguins foraging, off Adélie Land, during the late breeding season 1997. Depth of foraging was recorded for nine birds whose diet ranged from krill only to predominantly fish. Previous studies suggested that penguins capturing fish dived to shallower depths, but this could not be verified in our study. Moreover, most other foraging parameters did not indicate any significantly different patterns relative to prey caught. Only swim speed in the commuting phase, but not in the undulatory, bottom phase of deep dives differed with respect to prey consumed. We conclude that Adélie penguins foraging in open waters may change their foraging behaviour only slightly depending on the prey. Under other conditions, these changes may become more significant.