Foraging behaviour of king penguins (Aptenodytes patagonicus) in relation to oceanography at South Georgia and Kerguelen

Understanding the levels of variability in oceanographic features where marine predators forage is critical for understanding variability in an animal's foraging behaviour and reproductive success, and for assessing their potential reactions to environmental change. In this thesis, I examine the foraging behaviour of king penguins (Aptenodytes patagonicus) in relation to oceanographic features in both horizontal and vertical dimensions. I used ARGOS and Global Positioning System tracking data combined with Time-Depth-Temperature-Recorder data to follow the at-sea movements for penguins breeding at South Georgia and Kerguelen. Combining penguin behaviour with oceanographic data at the surface and at depth allowed me to explore how animals adjust their horizontal and vertical movements in response to their environment. In this context J investigated how horizontal habitat use may relate to different Antarctic Circumpolar Current frontal zones, and how hydrological structures at depth may impact diving behaviour. At both study locations, the Polar Front (PF) and cold-water features of southern origin were key features used during foraging. The importance of local habitat was reflected in their use of mesoscale eddies at South Georgia, and bathymetry-related upwelling at Kerguelen. The main features used at depth, during prey pursuit, were the thermocline and Winter Water. Penguins also explored Circumpolar Deep Water, which appears to represent an important foraging niche for birds when under increased breeding or environmental constraints. Variability in the PF and in cold-water features in the foraging area significantly affected penguin behaviour. For example, penguins showed altered behavioural responses and low reproductive success following shifts in key oceanographic features during one breeding season. My study of king penguin foraging behaviour in two sectors of the Southern Ocean has generated these key insights into foraging relationships with oceanography, and into penguin's adaptive capacities to environmental variability. This is of importance for assessing possible reactions of king penguins towards environmental change.EThOS - Electronic Theses Online ServiceGBUnited Kingdo