Frightening methods and devices/stimuli to prevent mammal damage--a review
Various frightening stimuli, primarily visual and acoustic, have been used to prevent or alleviate damage by depredating mammals (e.g., deer (Odocoileus spp.), raccoons (Procyon lotor), tree squirrels (Sciurus spp.), coyotes (Canis latrans). Frightening methods are most appropriate for use where a crop or situation needs protection from pest mammals for only a period of a few days or weeks. The ability of animals to habituate to such stimuli limits their long-term usefulness. Against nocturnal species, various types of lights and noisemakers are the most useful. Combining acoustic and visual stimuli can enhance effectiveness, while varying the techniques used, the placement of frightening devices, and/or the timing sequence can delay habituation. Other types of physical frightening stimuli are also reviewed.