title: Dual foraging and pair coordination during chick provisioning by Manx shearwaters: empirical evidence supported by a simple model.
abstract: The optimal allocation of time and energy between one's own survival and offspring survival is critical for iteroparous animals, but creates a conflict between what maximises the parent's fitness and what maximises fitness of the offspring. For central-place foragers, provisioning strategies may reflect this allocation, while the distance between central-places and foraging areas may influence the decision. Nevertheless, few studies have explored the link between life history and foraging in the context of resource allocation. Studying foraging behaviour alongside food load rates to chicks provides a useful system for understanding the foraging decisions made during parent-offspring conflict. Using simultaneously deployed GPS and time-depth recorders, we examined the provisioning strategies in free-living Manx shearwaters Puffinus puffinus, which were caring for young. Our results showed a bimodal pattern, where birds alternate short and long trips. Short trips were associated with higher feeding frequency and larger meals than long trips, suggesting that long trips were performed for self-feeding. Furthermore, most foraging was carried out within 100 km of sea fronts. A simple model based on patch quality and travel time shows that for Manx shearwaters combining chick feeding and self-maintenance, bimodal foraging trip durations optimise feeding rates.
authors.affiliation: Oxford University, Department of Zoology, South Parks Road, Oxford OX1 3PS, UK akikosho@gmail.com tim.guilford@zoo.ox.ac.uk.
authors.forename: Akiko
authors.initials: A
authors.lastname: Shoji
authors.affiliation: University of Ottawa, Department of Mathematics, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Aris-Brosou
authors.affiliation: Oxford University, Department of Zoology, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Annette
authors.initials: A
authors.lastname: Fayet
authors.affiliation: Oxford University, Department of Zoology, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Oliver
authors.initials: O
authors.lastname: Padget
authors.affiliation: Oxford University, Department of Zoology, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Perrins
authors.affiliation: Oxford University, Department of Zoology, South Parks Road, Oxford OX1 3PS, UK akikosho@gmail.com tim.guilford@zoo.ox.ac.uk.
authors.forename: Tim
authors.initials: T
authors.lastname: Guilford
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001717:Birds / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D004242:Diving; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D008297:Male; D009425:Nesting Behavior / Q000502:physiology; D013997:Time Factors; D014852:Wales
keywords: Bio-logging; Diving; Foraging strategy; GPS; Puffinus puffinus