title: The cost of prospecting for dispersal opportunities in a social bird.
abstract: Understanding why individuals delay dispersal and become subordinates within a group is central to studying the evolution of sociality. Hypotheses predict that dispersal decisions are influenced by costs of extra-territorial prospecting that are often required to find a breeding vacancy. Little is known about such costs, partly because it is complicated to demonstrate them empirically. For example, prospecting individuals may be of inferior quality already before prospecting and/or have been evicted. Moreover, costs of prospecting are mainly studied in species where prospectors suffer from predation risk, so how costly prospecting is when predators are absent remains unclear. Here, we determine a cost of prospecting for subordinate Seychelles warblers, Acrocephalus sechellensis, in a population where predators are absent and individuals return to their resident territory after prospecting. Prospecting individuals had 5.2% lower body mass than non-prospecting individuals. Our evidence suggests this may be owing to frequent attacks by resident conspecifics, likely leading to reduced food intake by prospectors. These results support the hypothesis that energetic costs associated with dispersal opportunities are one factor influencing dispersal decisions and shaping the evolution of delayed dispersal in social animals.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK Behavioural and Physiological Ecology, GELIFES, University of Groningen, PO Box 11103, 9700CC Groningen, The Netherlands sjoukeannekingma@gmail.com.
authors.forename: Sjouke A
authors.identifier: 0000-0002-6737-7975
authors.initials: SA
authors.lastname: Kingma
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, PO Box 11103, 9700CC Groningen, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Komdeur
authors.affiliation: Behavioural and Physiological Ecology, GELIFES, University of Groningen, PO Box 11103, 9700CC Groningen, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Hammers
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK Nature Seychelles, PO Box 1310, Mahé, Seychelles.
authors.forename: David S
authors.initials: DS
authors.lastname: Richardson
mesh_terms: D063147:Animal Distribution / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight; D005260:Female; D008297:Male; D046109:Passeriformes / Q000502:physiology*; D012750:Seychelles; D012919:Social Behavior; D013731:Territoriality
keywords: benefits of philopatry; cooperative breeding; delayed dispersal