Polar Biology 24, 467-470 (2001)
Time/depth usage of Adelie penguins; an approach based on dive angles.
Ropert-Coudert Y, Kato A, Baudat J, Bost C-A, Le Maho Y, Naito Y
Data on the swim speed, dive depth and feeding rates of three Adelie penguins Pygoscelis adeliae foraging in summer 1998/1999 in Adelie Land, Antarctica were collected using dorsally-mounted loggers in tandem with oesophageal temperature sensors. Swim speed could be integrated together with the rate of change of depth to determine dive and return-to surface angles. Overall, birds increased rates of change of depth during commuting phases so that dive angles were steeper in dives terminating at greater depths. Angles of descent and ascent during feeding dives were greater than during non-feeding dives. Although variation in the descent angle over time of particular dives was generally less than 10｡, the angles of the ascent phases followed substantial fluctuations. The importance of selecting the optimum descent and ascent angles with respect to prey exploitation, including consideration of oxygen stores and time gained in the feeding area over the course of a dive by diving at a steeper angle, is discussed.
PG01-4
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