Polar Biology

, Volume 35, Issue 1, pp 1–13 | Cite as

Non-consumptive factors affecting foraging patterns in Antarctic penguins: a review and synthesis

Review

Abstract

Recent research has clearly shown that the fear of predation, i.e. aversion to taking risks, among mesopredators or grazers, and not merely flight from an apex predator to avoid predation, is an important aspect of ecosystem structuring. In only a few, though well-documented cases, however, has this been considered in the marine environment. Herein, we review studies that have quantified behavioral responses of Adélie penguins Pygoscelis adeliae and emperor penguins Aptenodytes forsteri to the direct presence of predators, and question why the penguins avoid entering or exiting the water at night. We also show, through literature review and new analyses of Adélie penguin diving data, that Antarctic penguins are capable of successful prey capture in the dark (defined here as <3.4 lux). Finally, we summarize extensive data on seasonal migration relative to darkness and prey availability. On the basis of our findings, we propose that penguins’ avoidance of foraging at night is due to fear of predation, and not to an inability to operate effectively in darkness. We further propose that, at polar latitudes where darkness is more a seasonal than a year-round, daily feature, this “risk aversion” affects migratory movements in both species, consistent with the “trade-off” hypothesis seen in other marine vertebrates weighing foraging success against predation risk in their choice of foraging habitat. Such non-consumptive, behavioral aspects of species interactions have yet to be considered as important in Southern Ocean food webs, but may help to explain enigmatic movement patterns and choice of foraging grounds in these penguin species.

Keywords

Adélie penguin Apex predator Emperor penguin Foraging habitat Killer whale Leopard seal Mesopredator Predation Predation fear Risk balancing 

Notes

Acknowledgments

This paper was written under grant OPP-0440643 from the US National Science Foundation. Logistic support was expertly supplied by the US Antarctic Research Program. This work was accomplished under Antarctic Conservation Permit ACA-2006-010, and under Institutional Animal Care Use Committee permit #878. We thank D. Karentz for supplying and helping with the radiometer deployment; and J. Eastman, R. L. Pitman, R. Hill, G. L. Kooyman, B. Wienecke, C. Barbraud, R. Ydenburg and three anonymous reviewers for very helpful information or critical comments. This is contribution 1812 of PRBO Conservation Science.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.H.T. Harvey and AssociatesLos GatosUSA
  2. 2.PRBO Conservation SciencePetalumaUSA

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