Sympatric Breeding Auks Shift between Dietary and Spatial Resource Partitioning across the Annual Cycle

• Published in: PLoS ONE
• Main Authors: Linnebjerg, Jannie, Fort, Jérôme, Guilford, Tim, Reuleaux, Anna, Mosbech, Anders, Frederiksen, Morten
• Other Authors: Department of Biological Sciences, Aarhus University, Animal Behaviour Research Group, University of Oxford Oxford, Arctic Research Centre, Aarhus University Aarhus
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Alca torda; common guillemot; Razorbill; Uria aalge; uria
• Online Access: https://hal.archives-ouvertes.fr/hal-01100403; https://hal.archives-ouvertes.fr/hal-01100403/document; https://hal.archives-ouvertes.fr/hal-01100403/file/Linnebjerg%20et%20al%202013_PLoS%20ONE.pdf; https://doi.org/10.1371/journal.pone.0072987

International audience When species competing for the same resources coexist, some segregation in the way they utilize those resources isexpected. However, little is known about how closely related sympatric breeding species segregate outside thebreeding season. We investigated the annual segregation of three closely related seabirds (razorbill Alca torda,common guillemot Uria aalge and Brünnich’s guillemot U. lomvia) breeding at the same colony in SouthwestGreenland. By combining GPS and geolocation (GLS) tracking with dive depth and stable isotope analyses, wecompared spatial and dietary resource partitioning. During the breeding season, we found the three species tosegregate in diet and/or dive depth, but less in foraging area. During both the post-breeding and pre-breedingperiods, the three species had an increased overlap in diet, but were dispersed over a larger spatial scale. Divedepths were similar across the annual cycle, suggesting morphological adaptations fixed by evolution. Prey choice,on the other hand, seemed much more flexible and therefore more likely to be affected by the immediate presence ofpotential competitors.