Meeting Abstract
Parental care (e.g. provisioning nestlings) is widely assumed to be costly, and life-history theory predicts that individuals that invest more in parental care should benefit in terms of number of offspring produced but that increased parental care might come at a cost in terms of decreased future fecundity and/or survival. However, the notion that parents that work “harder”, commonly measured by the rate at which parents visit the nest box to provision their chicks, produce more, fitter chicks is surprisingly poorly supported. One potential reason for this apparent lack of relationship between measured work load during parental care and breeding productivity is that nest visit rate does not provide a good measure of foraging effort (even though this is the most commonly used metric). During chick-rearing, provisioning birds can adjust their foraging behavior in many other ways, e.g. varying load size, prey type, foraging distance, etc. Here, we investigated effects of handicapping (i.e. wing clipping) on parental effort during reproduction in breeding European starlings, Sturnus vulgaris. Using an automated radio telemetry system we tracked individual breeding females 24/7 for the entirety of the breeding period. Our data suggests that there is marked variation in daily activity patterns amongst individuals. We predict that individuals with an increased activity rate will bring back a greater proportion of their preferred prey type, Tipulidae larvae. Consequently, individuals with greater activity rates will have a greater productivity and overall chick quality. We also determine repeatability of variation in activity, comparing first and second breeding attempts, for several provisioning metrics (provisioning rate, activity level, load size, and prey type) and whether that individual variation explains breeding productivity.
