Can Central Place Foraging Theory Predict Material Collection Behaviours of the Eurasian Beaver (Castor fiber)?

Central place foragers (CPF) are animals that return collected resources to their central place. During foraging trips, individuals may exhibit different strategies and either prioritize energy maximizing (EM) during foraging bouts or minimize the time (Time minimising, TM) they spend away from their central place. The exhibited strategy may depend on the composition and distribution of the desired resources and costs of local threats. Beavers exhibit CPF, collecting timber for food and for use in constructions. We assessed trees felled by beavers and control, unfelled trees at two rivers in England and Norway that differed in resource availability and distribution and history of beaver occupation. We evaluated evidence to support or refute EM and TM strategies. We found that beavers were selective in the size and species of trees that they felled. However, the beavers differed between sites in whether their felling was spatially clustered or more randomly distributed. These results suggest site-dependent variation in the predictive value of the EM and TM strategies of CPF for beaver material collection behaviors. These differences between the two sites may reflect different optimal foraging strategies driven by different lengths of occupation by beavers in the vicinity.