Abstract: Seabirds are central place foragers, relying on prey that is patchily distributed and of variable predictability. Species travelling at a high energetic cost are more strongly dependent on spatially predictable prey. This is the case for diving petrels Pelecanoides spp., which are small Procellariiformes that feed by pursuit diving and travel by flapping constantly. Despite their abundance and importance as zooplankton consumers, information on the foraging strategy of diving petrels is still lacking. The detailed at-sea movements and the trophic niche of the South Georgian diving petrel P. georgicus was investigated for the first time using miniaturized GPS and the stable isotope method, respectively. Overall, South Georgian diving petrels from the Kerguelen Islands performed unexpected, direct and long-distance trips (mean foraging range: 191-217 km) to the Antarctic Polar Front, south of the archipelago. This foraging ground is a productive and predictable area, where the birds stopped and fed at the distal part of their trip. Blood isotopic values indicate that the tracked birds fed consistently on macrozooplankton. Such a distant oceanic feeding strategy contrasts with the coastal foraging patterns of the closely related common diving petrel P. urinatrix. Commuting to a more distant but easily accessible resource allows South Georgian diving petrels to cope with their high commuting costs, and to segregate spatially from the sympatric common diving petrel during the breeding season.

Abstract: Albatrosses are amongst the most globally-threatened species and fisheries bycatch is one of the major conservation issues worldwide. Among the albatrosses the Amsterdam albatross is listed as one of the most endangered species. Within the current National Plan of Actions framework, the present study outlines the first results of a multi-year survey evaluating juvenile dispersal and immature at sea distribution using geolocation and conservation implications. Here we report the first evidence of an Amsterdam albatross wandering for extensive periods outside the Indian Ocean, in the Pacific Ocean. This unprecedented and novel finding is discussed in terms of overlaps with fisheries and conservations issues. This study brings new insights on movements of vagrant stages of an endangered species, paving the way for refined assessments updates of species vulnerability to ongoing anthropogenic threats while providing basic conservation guidance. This makes it possible to point out the responsibility of the various management bodies both for the high seas regional fisheries management organisations and for exclusive economic zones.