Foraging under contrasting oceanographic conditions: the gentoo penguin at Kerguelen Archipelago
Résumé
Coastal seabirds are bound to be dependent on local marine resources. We hypothesize that the localization of the breeding colony will influence the foraging patterns of such predators. The foraging behavior of gentoo penguins Pygoscelis papua was investigated in contrasting marine environments at Kerguelen Archipelago over the 2002–03 and 2003–04 breeding seasons. Using timedepth recorders (TDRs) and satellite transmitters, we describe the at-sea distribution and diving behavior of gentoo penguins breeding in 2 colonies facing the open sea (Open Sea 1 and Open Sea 2) and 1 colony protected in a closed bay (Closed Sea). The foraging behavior varies extensively across the Kerguelen Archipelago, almost as much as it does over the entire range of the species. Different foraging strategies emerge, depending on the local conditions: large foraging ranges, long trips, long benthic dives on demersal fish at Open Sea colonies versus small foraging ranges, short trips, short pelagic dives on swarming crustaceans at Closed Sea, for a same foraging effort. The diving behavior of the gentoo penguin therefore varies as a function of the locality and the site, closely related to prey availability. This study demonstrates the importance of foraging plasticity as a fundamental aspect of life history in coastal marine predators.