MEPS 323:239-251 (2006)  -  doi:10.3354/meps323239

Foraging dynamics of macaroni penguins Eudyptes chrysolophus at South Georgia during brood-guard

P. N. Trathan1,*, C. Green1, J. Tanton1, H. Peat1, J. Poncet2, A. Morton1

1British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
2Golden Fleece Expeditions, Beaver Island, Stanley, Falkland Islands FIQQ 1ES

ABSTRACT: We used satellite telemetry methods to study macaroni penguins at South Georgia to determine how they ranged from their colonies during the early part of their breeding season at a time when they are constrained to return to their chicks on a near-daily basis. The principal objectives of this study were to examine whether these penguins exploit major oceanographic features where prey may be more predictable, whether birds from one colony forage in separate locations to those from nearby colonies, or whether they range evenly over the available area. Results show that the penguins did not range evenly, that birds from one colony tended to forage in locations separate from those used by birds from nearby colonies (or at least overlap was restricted), and that though birds from some colonies foraged within waters influenced by major oceanographic features such as the southern Antarctic Circumpolar Current front, not all birds in the region focused on such areas, as some birds foraged in other oceanographic contexts. The results from this study highlight the complexity of foraging dynamics for colonially nesting seabirds; they also help inform management models currently being developed for Antarctic krill fisheries, which are a potential competitor for the main prey of macaroni penguins.

KEY WORDS: Macaroni penguin · Foraging · Oceanography · Satellite telemetry · South Georgia

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