Combined stomach content, lipid and stable isotope analyses reveal spatial and trophic partitioning among three sympatric albatrosses from the Southern Ocean

• Published in: Marine Ecology Progress Series
• Main Authors: Connan, Maëlle, Mcquaid, Christopher D., Bonnevie, Bo T., Smale, Malcolm J., Cherel, Yves
• Other Authors: Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Department of Zoology and Entomology Rhodes University, Rhodes University, Grahamstown, Department of Zoology and Entomology Pretoria, University of Pretoria South Africa, Information Technology Division, Port Elizabeth Museum at Bayworld, Zoology Department, Nelson Mandela University Port Elizabeth, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: Phoebetria palpebrata; Phoebetria fusca; Thalassarche chrysostoma; Trophic segregation; Spatial segregation; Moulting period; Breeding season; [SDE]Environmental Sciences; Antarc*; Antarctic; Marion Island; Southern Ocean
• Online Access: https://hal.science/hal-00958821; https://doi.org/10.3354/meps10606

International audience A combination of dietary techniques that integrate data on food and feeding habits over days, weeks and months was used to investigate resource partitioning among 3 sympatric albatrosses, namely the grey-headed Thalassarche chrysostoma (GHA), light-mantled sooty Phoebetria palpebrata (LMSA) and sooty Phoebetria fusca (SA) albatrosses. These medium-size albatrosses typically breed every 2 yr, and Marion Island (southern Indian Ocean) is the only breeding site where the 3 species are accessible. Stomach content analysis provided dietary information about the most recent meal, analysis of fatty acids in stomach oils about the last foraging trip, and carbon and nitrogen stable isotope values of blood and feathers about the chick-rearing (breeding) and moulting periods, respectively. The combination of techniques highlighted a complex pattern regarding the spatial and trophic segregation between the 3 species. During both seasons, SA were spatially segregated from LMSA and GHA, foraging farther north (in subantarctic and subtropical areas) than the 2 other species (subantarctic and Antarctic waters). When feeding for themselves during the breeding season (blood isotopic signatures), adults showed a clear spatial segregation. When bringing back food for their chicks (stomach contents), trophic segregation became obvious, with the 2 Phoebetria species specializing mostly on squids. The results illustrate how sympatrically breeding birds can show niche partitioning through both spatial segregation and prey specialization.