Feeding behaviour of free–ranging penguins determined by oesophageal temperature

Sea birds play a major role in marine food webs, and it is important to determine when and how much they feed at sea. A major advance has been made by using the drop in stomach temperature after ingestion of ectothermic prey.This method is less sensitive when birds eat small prey or when the stomach...

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Bibliographic Details
Published in:Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2001-01, Vol.268 (1463), p.151-157
Main Authors: Charrassin, Jean-Benoît, Kato, Akiko, Handrich, Yves, Sato, Katsufumi, Naito, Yasuhiko, Ancel, Andre, Bost, Charles-André, Gauthier-Clerc, Michel, Ropert-Coudert, Yan, Le Maho, Yvon
Format: Article
Language:English
Subjects:
Animals
Aptenodytes patagonicus
Birds
Birds - physiology
Body Temperature
Diving
Esophagus - physiology
Feeding Behavior - physiology
Foraging
Geophysics
Ingestion
King Penguin
Loggers
Oceans
Oesophageal Temperature
Penguins
Physics
Sea birds
Sensors
Stomach
Thermistors
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Summary:Sea birds play a major role in marine food webs, and it is important to determine when and how much they feed at sea. A major advance has been made by using the drop in stomach temperature after ingestion of ectothermic prey.This method is less sensitive when birds eat small prey or when the stomach is full. Moreover, in diving birds, independently of food ingestion, there are fluctuations in the lower abdominal temperature during the dives. Using oesophageal temperature, we present here a new method for detecting the timing of prey ingestion in free-ranging sea birds, and, to our knowledge, report the first data obtained on king penguins (Aptenodytes patagonicus). In birds ashore, which were hand-fed 2-15g pieces of fish, all meal ingestions were detected with a sensor in the upper oesophagus. Detection was poorer with sensors at increasing distances from the beak. At sea, slow temperature drops in the upper oesophagus and stomach characterized a diving effect per se. For the upper oesophagus only, abrupt temperature variations were superimposed, therefore indicating prey ingestions. We determined the depths at which these occurred. Combining the changes in oesophageal temperatures of marine predators with their diving pattern opens new perspectives for understanding their foraging strategy, and, after validation with concurrent applications of classical techniques of prey survey, for assessing the distribution of their prey.
ISSN:0962-8452
1471-2954
DOI:10.1098/rspb.2000.1343