Assessment of prey consumption by Magellanic penguins in Patagonian colonies

SALA, J.E.; WILSON, R.P.; QUINTANA, F.

Victoria, Columbia Británica

Congreso; 1st World Seabird Conference; 2010

Pacific Seabird Group

Following procedures outlined in Simeone & Wilson (2003), we used undulations in the dive profile of 15 logger-equipped Magellanic Penguin (Spheniscus magellanicus) foraging from three Patagonian colonies; Bahía Bustamente (BB), Puerto Deseado (PD) and Puerto San Julián (PSJ), all located in Argentina between 45-54° S, to estimate the number of prey captured by the birds. We calculated the catch per unit time (CPUT) for foraging trips undertaken during the early chick-rearing period. Numbers of prey caught and CPUT were different between colonies. Birds from PD caught the highest number of prey per foraging trip (2325 ± 1401 vs. 1839 ± 944 and 460 ± 220 for PSJ and BB, respectively) with CPUT values of 130 ± 36 prey per hour (up to 2.5 times greater than BB). However, the number of dives performed by penguins from PSJ was two to five times higher than those made by birds from PD and BB, respectively. Consideration of other indirect measurements of the foraging effort (trip durations and foraging bout lengths) and success (the type of prey consumed), penguins from BB seem to the least successful. Our results suggest that behavioral proxies for foraging success and effort may inform conservation initiatives for penguins and other top predator in a changing Patagonian Sea.