title: Foraging flexibility and search patterns are unlinked during breeding in a free-ranging seabird.
abstract: In order to maximize foraging efficiency in a varying environment, predators are expected to optimize their search strategy. Environmental conditions are one important factor affecting these movement patterns, but variations in breeding constraints (self-feeding vs. feeding young and self-feeding) during different breeding stages (incubation vs. chick-rearing) are often overlooked, so that the mechanisms responsible for such behavioral shifts are still unknown. Here, to test how search patterns are affected at different breeding stages and to explore the proximate causes of these variations, we deployed data loggers to record both position (global positioning system) and dive activity (time-depth recorders) of a colonial breeding seabird, the razorbillAlca torda. Over a period of 3 years, our recordings of 56 foraging trips from 18 breeders show that while there is no evidence for individual route fidelity, razorbills exhibit higher foraging flexibility during incubation than during chick rearing, when foraging becomes more focused on an area of high primary productivity. We further show that this behavioral shift is not due to a shift in search patterns, as reorientations during foraging are independent of breeding stage. Our results suggest that foraging flexibility and search patterns are unlinked, perhaps because birds can read cues from their environment, including conspecifics, to optimize their foraging efficiency.
authors.affiliation: Department of Zoology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Akiko
authors.initials: A
authors.lastname: Shoji
authors.affiliation: Department of Mathematics and Statistics, University of Ottawa, Ottawa, ON K1N 6N5 Canada.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Aris-Brosou
authors.affiliation: The Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL UK.
authors.forename: Ellie
authors.initials: E
authors.lastname: Owen
authors.affiliation: The Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Bolton
authors.affiliation: Edward Grey Institute of Field Ornithology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Dave
authors.initials: D
authors.lastname: Boyle
authors.affiliation: Department of Zoology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Annette
authors.initials: A
authors.lastname: Fayet
authors.affiliation: Department of Zoology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Dean
authors.affiliation: Department of Zoology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Holly
authors.initials: H
authors.lastname: Kirk
authors.affiliation: Institute of Zoology, Zoological Society of London, Regents Park, London, NW1 4RY UK.
authors.forename: Robin
authors.initials: R
authors.lastname: Freeman
authors.affiliation: Edward Grey Institute of Field Ornithology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Perrins
authors.affiliation: Department of Zoology, University of Oxford, Oxford, Oxfordshire UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Guilford