Half a World Apart? Overlap in Nonbreeding Distributions of Atlantic and Indian Ocean Thin-Billed Prions

• Published in: PLOS ONE
• Main Authors: Quillfeldt, Petra, Cherel, Yves, Masello, Juan F., Delord, Karine, Mcgill, Rona A. R., Furness, Robert, Moodley, Yoshan, Weimerkirsch, Henri
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDE]Environmental Sciences; Indian; Kerguelen; Southern Ocean
• Online Access: https://hal.archives-ouvertes.fr/hal-01199776; https://doi.org/10.1371/journal.pone.0125007

International audience Distant populations of animals may share their non-breeding grounds or migrate to distinctareas, and this may have important consequences for population differentiation and dynamics.Small burrow-nesting seabirds provide a suitable case study, as they are often restrictedto safe breeding sites on islands, resulting in a patchy breeding distribution. Forexample, Thin-billed prions Pachyptila belcheri have two major breeding colonies morethan 8,000 km apart, on the Falkland Islands in the south-western Atlantic and in the KerguelenArchipelago in the Indian Ocean. We used geolocators and stable isotopes to compareat-sea movements and trophic levels of these two populations during their nonbreedingseason, and applied ecological niche models to compare environmental conditionsin the habitat. Over three winters, birds breeding in the Atlantic showed a high consistencyin their migration routes. Most individuals migrated more than 3000 km eastwards,while very few remained over the Patagonian Shelf. In contrast, all Indian Ocean birds migratedwestwards, resulting in an overlapping nonbreeding area in the eastern Atlantic sectorof the Southern Ocean. Geolocators and isotopic signature of feathers indicated thatprions from the Falklands moulted at slightly higher latitudes than those from Kerguelen Islands.All birds fed on low trophic level prey, most probably crustaceans. The phenology differednotably between the two populations. Falkland birds returned to the Patagonian Shelfafter 2-3 months, while Kerguelen birds remained in the nonbreeding area for sevenmonths, before returning to nesting grounds highly synchronously and at high speed. Habitatmodels identified sea surface temperature and chlorophyll a concentration as importantenvironmental parameters. In summary, we show that even though the two very distant populationsmigrate to roughly the same area to moult, they have distinct wintering strategies:They had significantly different realized niches and timing which may contribute to ...