At-sea behavioural ecology of the endangered MacGillivray’s prion from Saint Paul Island: combining tracking and stable isotopes

• Published in: Marine Ecology Progress Series
• Main Authors: Delord, Karine, Cherel, Yves, Roy, Amédée, Bustamante, Paco, Swadling, Kerrie M, Weimerskirch, Henri, Bost, Charles‐andré, Barbraud, Christophe
• 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), MARine Biodiversity Exploitation and Conservation - MARBEC (UMR MARBEC ), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Institute for Marine and Antarctic Studies Hobart (IMAS), University of Tasmania Hobart, Australia (UTAS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Pachyptila macgillivrayi; At-sea distribution; Activity pattern; Southern Indian Ocean; Geolocation; GPS; Seabirds; Bill width; Trophic position; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; Antarctic; Indian; Saint-Paul; Antarc*; Saint-Paul Island
• Online Access: https://hal.science/hal-03790607; https://hal.science/hal-03790607/document; https://hal.science/hal-03790607/file/Delord%20et%20al.%202022%20MEPS.pdf; https://doi.org/10.3354/meps14136

International audience Seabirds play important roles as marine ecosystem sentinels. Studying their at-sea ecology is essential for understanding how environmental variability affects their populations. However, the at-sea ecology of small-sized temperate seabirds remains poorly studied. We explored the at-sea ecology of the Critically Endangered MacGillivray’s prion Pachyptila macgillivrayi breeding on the subtropical Saint Paul Island. Using global location sensor loggers and stable isotope analysis, we investigated movements, migratory strategies, at-sea activity and moulting period, and characterized the isotopic niche of tracked individuals. During incubation, MacGillivray’s prions remained in temperate waters north of the Subtropical Front, possibly feeding on prey caught in cold eddies. During the inter-breeding period, individuals wintered almost equally to the north and south of the Subtropical Front in 2 distinct sectors (Tasman Sea and Southwest Indian Ridge). Daily activity varied seasonally, and individuals overwintering in the Tasman Sea spent more time flying at night when moonlight intensity was high. Moulting occurred after the breeding period and lasted longer compared to other prion species. Isotopic data suggest a higher dietary proportion of low trophic-level prey for MacGillivray’s prions than for Antarctic and slender-billed prions, highlighting trophic segregation in relation to bill width. Our study provides new evidence to understand the suite of adaptations allowing the abundant prion species to coexist by feeding on prey of different sizes. Contrary to the majority of seabird species, MacGillivray’s prions from Saint Paul Island exhibited 2 migratory tactics with associated differences in at-sea activity, leading to questions about the origin of these differences.