LEARNING ABOUT FOOD - STARLINGS, SKINNER BOXES, AND EARTHWORMS

Despite its importance as a tool for understanding a wide range of ani mal behavior, the study of reinforcement schedules in the laboratory h as suffered from difficulties in the biological interpretation of its findings. This study is an operant-laboratory investigation of the abi lity of European starlings, Sturnus vulgaris, to learn to respond adap tively to the problem of foraging on patchily distributed prey that ar e uncertainly located in space. In order to maximize the biological re levance of the laboratory study, variation in the aggregation of earth worms, Lumbricus terrestris (a prey species), was rigorously quantifie d from the field, and the experimental birds were presented with reinf orcement schedules designed to represent the extremes of the observed variation. The results demonstrate that, even for a single prey specie s, the degree to which individuals are aggregated can vary markedly ov er a range of spatial scales, and that starlings can rapidly learn to respond, in an adaptive manner, to these variations. These findings su ggest that starlings are capable of adjusting their behavior to facili tate the efficient exploitation of prey that occurs in patches of an u ncertain nature, and thus illustrate the heuristic value of an ecologi cally informed operant-laboratory approach to studying foraging behavi or.