Models of natural predators could make prey animals anxious and thereby have a deterring effect.
One study from Connecticut, USA, evaluated the impact of a plastic model of great horned owl (Bubo virginianus) to deter American crows (Corvus brachyrhynchos) from tomatoes and cantaloupes. When the model was unanimated there was no difference in crop losses between the treatment and control plots in one trial, while losses were 46 % and 52 % lower in treatment plots in two additional trials. When models were wind-powered, crop losses were 81 % and 100 % less in the treatment plots. When models were battery powered, crop losses were 70 % and 100 % lower in the treatment plots, and when models were both wind and battery powered losses were 81 % lower.
