Foraging behaviour and habitat-use drives niche segregation in sibling seabird species

• Published in: Royal Society Open Science
• Main Authors: Reisinger, Ryan, Carpenter-Kling, Tegan, Connan, Maëlle, Cherel, Yves, Pistorius, Pierre
• Other Authors: Institute for Coastal and Marine Research and Department of Zoology South Africa, Nelson Mandela Metropolitan University Port Elizabeth, South Africa, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (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 2020
• Subjects: diet; stable isotopes; movement; competition; partitioning; habitat selection; [SDE]Environmental Sciences; Indian; Giant Petrels; Marion Island
• Online Access: https://hal.archives-ouvertes.fr/hal-02940622; https://doi.org/10.1098/rsos.200649

International audience To mediate competition, similar sympatric species are assumed to use different resources, or the same but geographically separated resources. The two giant petrels (Macronectes spp.) are intriguing in that they are morphologically similar seabirds with overlapping diets and distributions. To better understand the mechanisms allowing their coexistence, we investigated intra-and interspecific niche segregation at Marion Island (Southern Indian Ocean), one of the few localities where they breed in sympatry. We used GPS tracks from 94 individuals and remote-sensed environmental data to quantify habitat use, combined with blood carbon and nitrogen stable isotope ratios from 90 individuals to characterize their foraging habitat and trophic ecology. Females of both species made distant at-sea foraging trips and fed at a similar trophic level. However, they used distinct pelagic habitats. By contrast, males of both species mainly foraged on or near land, resulting in significant sexual segregation, but high interspecific habitat and diet overlap. However, some males showed flexible behavioural strategies, also making distant, pelagic foraging trips. Using contemporaneous tracking, environmental and stable isotope data we provide a clear example of how sympatric sibling species can be segregated along different foraging behaviour dimensions.