Wintering strategies of two king penguin populations of the Southern Indian Ocean

The king penguin Aptenodytes patagonicus is an important model species of the Southern Ocean. While there is extensive knowledge on the foraging movement of this species during the summer in the early chick-provisioning period, little information is available for the winter period. To fill this gap, we tracked 13 individuals during the winter from 2 neighboring populations of the Southern Indian Ocean, namely the Kerguelen and the Crozet Archipelagos, and examined penguin locations with respect to remote sensing data. Tracked penguins from Kerguelen mostly headed east of the archipelago, while those from Crozet islands headed southwest. This resulted in contrasting latitudes used between the 2 wintering locations. The different directions taken possibly result from the distinct oceanic features around the 2 islands: at Kerguelen, extensive spring blooms transported east of the island might sustain prey well until the winter, offering favorable conditions for penguins. At Crozet, blooms are reduced in intensity and penguins might instead head south to benefit from the better foraging conditions near the sea ice. Such distinct foraging distributions relative to the 2 archipelagos are consistent with the at-sea distribution of other penguin species (e.g. Eudyptes spp.) breeding in the same localities. We highlight 2 distinct winter foraging strategies in neighboring king penguin populations, shaped by the contrasting oceanographic conditions surrounding their breeding sites.