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Breeding Jackass Penguins as pelagic predators

Bibliography: pages 187-191. / The foraging of breeding Jackass Penguins Spheniscus demersus was studied in and around southwestern Cape Province, Saldanha Bay (33⁰ S, 18⁰ E), South Africa. Penguins are difficult to observe at sea. Hence, I devised a number of new techniques for studying the foraging behaviour of Jackass Penguins at sea. I built electronic and autoradiographic remote-sensing devices to measure swimming speed, distance travelled and time spent at each depth by foraging Jackass Penguins. Penguin swimming speed was reduced in proportion to the cross-sectional area of the devices, and results derived from birds wearing the devices had to be interpreted accordingly. Penguins do not regurgitate their stomach contents when handled, so I constructed a wet-offloading stomach pump which extracted 100% of the stomach contents. Using this pump, I determined that the rate of digestion of fish and squid by Jackass Penguins differed. Care is needed in diet interpretations where both fish and squid are major food items.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/17653
Date January 1986
CreatorsWilson, Rory Paul
ContributorsSiegfried, Roy
PublisherUniversity of Cape Town, Faculty of Science, Percy FitzPatrick Institute of African Ornithology
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral Thesis, Doctoral, PhD
Formatapplication/pdf

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