Diving behaviour of chick-rearing Ade´lie Penguins at Edmonson Point, Ross Sea

The diving behaviour of chick-rearing Adélie penguins of Edmonson Point, Ross Sea, was analysed over two summer seasons (1994-1995 and 1995-1996). In 1994-1995, the study area was characterized by fast-ice persistency throughout season and by higher pack ice concentration than the following year, when fast-ice retreated earlier. Both females' and males' behaviour were examined, and we then compared diving characteristic between years and between guard and crèche stages of chick rearing. We found that changes in fast-ice extent influenced the transit times between colony and foraging grounds and that females conducted longer foraging trips, dived for longer periods and made more dives than males. The diving parameters were affected neither by the sex nor by the year, but differed between the breeding stages. Parents guarding chicks had longer dive and bottom phase durations than in crèche (dive duration: guard = 48 s, crèche = 42 s; bottom duration: guard = 34 s, crèche = 26 s), whilst they had shorter recovery times (e. g. post dive duration) (guard = 29 s, crèche = 32 s). Possible causes for the observed differences in diving behaviours are discussed. © 2010 Springer-Verlag.