Behavioural adaptations to breeding in a long-lived pelagic seabird

Abstract

The traits of organisms evolve by natural selection to maximise fitness; however, we do not observe Darwinian Demons. This is because all organisms face various types of constraint, which ultimately limit fitness. Reproduction is inextricably linked with fitness, and constraints on reproduction have extensive implications for evolution and adaptation. Two broad types of constraints on breeding are treated here. Firstly, breeding may be constrained by life-history trade-offs, perhaps most fundamentally in that current reproductive effort is constrained by its costs to future reproduction. Secondly, breeding may be constrained by the physical and ecological conditions and finite resources that are accessible from the breeding site, to which organisms may be tied to varying extents. The life-history and behaviour of animals are profoundly affected by these constraints, and they are especially influential in long-lived species. This thesis examines behavioural adaptations to each of these types of constraint in a long-lived pelagic seabird: the Manx Shearwater, Puffinus puffinus. Firstly, I investigate how patterns of behaviour vary between sexes and populations in preparation for breeding and how this variation is related to the ecological and physiological constraints faced by the groups during breeding. Secondly, I test the responsiveness of parents to changes in offspring hunger during food provisioning and discuss the influence of constraint by costs to future reproduction. I tackle these questions using well-established biologging methods to remotely monitor behaviour in a natural and experimental setting.</p