Laser scarecrows reduce avian corn-foraging propensity but not bout length in aviary trials

Behavioral mechanisms underlying avian deterrence by lasers in sweet corn are not known, and we evaluated them in a rigorous aviary experiment. Eighteen flocks of European starlings (Sturnus vulgaris) foraged on sweet corn for several days in control and laser treated plots with ripe sweet corn while data were collected on where birds were distributed and how long birds foraged on corn. In 16 trials, fresh ears were presented on wooden sticks, and in two trials birds foraged on natural corn grown from seed. Birds were sexed and boldness scores were obtained. We predicted that (a) birds would avoid foraging on ears in laser plots and (b) if they did feed, lasers would reduce foraging bout duration.