Comportement de recherche alimentaire pendant l´élevage du poussin chez le manchot empereur. Foraging Ecology of Emperor Penguins
Emperor penguins, Aptenodytes forsteri, play an important role as top predators in high Antarctic marine ecosystems. Being a central place forager the emperor penguin executes foraging trips to remote locations but consistently returns to a central place, the colony, to deliver food to the chick. The present study focuses on the critical two month-period before fledging, when maximum growth of chicks occurs and food demand is high at the Pointe Géologie emperor penguin colony. Using satellite telemetry we identified the foraging distribution and feeding grounds during late chick-rearing and before the adult moult in comparison. Depth records in addition allowed us to examine the diving behaviour at sea. Horizontal and vertical extent of penguin movement is here described over a single foraging trip in November 2005. The Area-Restricted-Search (ARS) (derived from the total distance spent travelling underwater over a defined time interval divided by the straight-line horizontal distance travelled during that period) and the Catch Per Unit Effort (CPUE) (derived from the putative number of prey caught (defined by points of inflections in the dive trace) divided by the time spent underwater) indices are used as a measure for the foraging activity to examine how birds allocate time to foraging in certain areas.