Springer-VerlagTokyo101640289-07711439-544430524811Journal of EthologyJ Ethol11110.1007/s10164-003-0111-1 Synchronous diving behavior of Adélie penguins VIDEO ARTICLE

• Main Authors: Akinori Takahashi, Katsufumi Sato, Jun Nishikawa, Yutaka Watanuki, Yasuhiko Naito, A. Takahashi, K. Sato, Y. Naito, J. Nishikawa, Y. Watanuki
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Pygoscelis adeliae; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.454.6351; http://polaris.nipr.ac.jp/~penguin/Official/Personal/atak/Taka2004JEthol.pdf

Abstract Synchronizing behavior with other conspecifics has been suggested as serving a function of increased for-aging efficiency. However, the potential costs associated with synchronization of behavior have rarely been studied. Adélie penguins Pygoscelis adeliae sometimes dive synchro-nously in small open waters surrounded by fast sea ice. We examined the diving behavior of three couples and one trio, which were observed to dive synchronously among groups of 12–47 birds for 1.7–4.5 h duration, with time-depth recorders. Timing of diving and surfacing differed slightly between individuals, and one bird tended to initiate diving earlier than the other. Although the duration of the dives differed only slightly between these birds, the maximum depth of the dives differed to a large extent, with one mem-ber tending to dive consistently deeper than the other bird in two out of the four cases. Vertical distances between tagged birds in the undulatory phases of the dives (pre-sumed feeding time) were greater than those in the descent and ascent phases, suggesting independent foraging by group members. Duration of the undulatory phase of the dives tended to be shorter in deeper-diving individuals than the others in the synchronously diving group, suggesting a potential cost of reduced feeding time to synchronize diving and surfacing with other birds. A digital video image relat-ing to the article is available at