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The diet of the Imperial Shag Phalacrocorax atriceps at a colony on New Island, Falkland/Malvinas Islands combining different sampling techniques

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Abstract

The diet of the Imperial Shag Phalacrocorax atriceps was studied on New Island, Falkland/Malvinas Islands during the 2008/2009 breeding season, with some additional data from 2007/2008. The diet comprised a large variety of prey, mainly fish, crustaceans and squid. In contrast to other species of the blue-eyed shag complex, prey not only consisted of benthic organisms but also included pelagic prey. Different sampling techniques were combined in order to obtain a comprehensive overview of the diet. Pellets, regurgitations and stomach contents yielded different results. We discuss the causes for these variations including different sample availability over time. In particular, the stomach analyses seem to overestimate the importance of squid based on the occurrence of squid beaks. For the pellet analyses, lobster krill accounted for the majority of the prey remains except during the second half of December (i.e. when young chicks were being attended), when fish was more important.

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Acknowledgments

We are grateful to the New Island Conservation Trust, Ian, Maria and Georgina Strange and Dan Birch who facilitated fieldwork. We wish to thank Alexander Arkhipkin, Gritta Veit-Köhler, Günter Purschke, Wiebke Brökeland and Charles Oliver Coleman for help in identification of prey remains. Financial support for fieldwork came from DFG-German Research Foundation, Germany (Qu 148/1-ff) and DAAD—the German Academic Exchange Service. Fieldwork at New Island was approved and co-funded by the Falkland Islands Government (Environmental Planning Office).

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Authors and Affiliations

  1. Max-Planck-Institut für Ornithologie, Vogelwarte Radolfzell, Schlossallee 2, 78315, Radolfzell, Germany

    Andreas Michalik, Hendrika J. van Noordwijk & Petra Quillfeldt

  2. Department of Biology/Chemistry, Experimental Ecology Group, University of Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany

    Andreas Michalik & Till Eggers

  3. Fisheries Department, Falkland Islands Government, PO Box 598, Stanley, Falkland Islands

    Paul Brickle

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  1. Andreas Michalik
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  2. Hendrika J. van Noordwijk
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  3. Paul Brickle
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  4. Till Eggers
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  5. Petra Quillfeldt
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Correspondence to Andreas Michalik.

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Michalik, A., van Noordwijk, H.J., Brickle, P. et al. The diet of the Imperial Shag Phalacrocorax atriceps at a colony on New Island, Falkland/Malvinas Islands combining different sampling techniques. Polar Biol 33, 1537–1546 (2010). https://doi.org/10.1007/s00300-010-0843-7

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  • DOI: https://doi.org/10.1007/s00300-010-0843-7

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