Diving Behavior and Energetics During Foraging Cycles in King Penguins

• Published in: Ecological Monographs
• Main Authors: Kooyman, G. L., Cherel, Y., Maho, Y. Le, Croxall, J. P., Thorson, P. H., Ridoux, V., Kooyman, C. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Emperor penguins; King Penguins
• Online Access: http://dx.doi.org/10.2307/2937173; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F2937173; https://onlinelibrary.wiley.com/doi/pdf/10.2307/2937173; https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/2937173

King Penguins are the second largest of all diving birds and share with their congener, Emperor Penguins, breeding habits strikingly different from other penguins. Our purpose was to determine the feeding behavior, energetics of foraging and the prey species, and compare these to other sympatric species of subantarctic divers. We determined: (1) general features of foraging behavior using time—depth recorders, velocity meters, and radio transmitters, (2) energetics by doubly labeled water, (3) food habits and energy content from stomach lavage samples, and (4) resting and swimming metabolic rate by oxygen consumption measurements. The average foraging cycle was ≈6 d, during which the mass gain of 30 birds was ≈2 kg. When at sea, the birds exhibit a marked pattern of shallow dives during the night, whereas deep dives of >100 m only occurred during the day. Maximum depth measured from 34 birds and 18 537 dives was 304 m, and maximum dive duration from 23 birds and 11 874 dives was 7.7 min. The frequency distribution of dive depth was bimodal, with few dives between 40 and 100 m. Overall, swim velocities when a bird was at sea averaged 2.1 m/s (N = 5), while descent and ascent rates of change in depth averaged 0.6 m/s for dives <60 m (N = 74) and 1.4 m/s for dives >150 m (N = 90). Night feeding dives occurred at a rate of ≈20 dives/h, and deep dives occurred at a rate of ≈5 dives/h. The energy consumption rate while resting ashore was 3.3 W/kg (N = 3) or 1.6 times the predicted standard metabolic rate (SMR). The average energy consumption rate while away from the colony was 10 W/kg (N = 8) or 4.6 x SMR, compared to 4.3 x SMR estimated from a time—energy budget. The latter value is based on an average metabolic rate of 4.2 W/kg for three birds while resting in 5°C water and 9.6 W/kg while swimming at 2 m/s, which was extrapolated from the average of three birds swimming at 1 m/s. The average energy intake based on 9 stomach content samples was nearly 24.6 kJ/g dry mass. The main prey by number are myctophid ...