U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

November 2003


We reviewed the learning processes and sensory capabilities of birds, with a special emphasis on chemical repellents and wildlife damage management. Repellents include several methods and devices used to manipulate behavior of birds in attempt to reduce damage or nuisance. Effective applications of chemical repellents to reduce bird damages are dependant upon an adequate understanding of the sensory modalities and modes of animal learning that are affected by a repellent. Chemical repellents can elicit withdrawal from specific or combined sensory stimuli or by producing learned avoidance via association between adverse postingestive effects and specific sensory cues. The application of repellents that elicit responses other than avoidance may result in a continued cycle of destructive sampling behavior and irritative escape. Avoidance is characterized by the discontinued sampling or consumption of foods, and/or the discontinued occupancy of places, previously associated with an aversive stimulus. Thus, an organism exhibits avoidance by wading an aversive event (eg, adverse postingestive effects) and its associated cues ( c g . taste, odor, visual cue) An understanding of how an animal senses and integrates such cues and aversive events is necessary for the development and application of effective repellents. Although the efficacy of chemical repellents has not been comprehensively evaluated, we review recent modeling efforts that have identified the chemical properties of existing and candidate repellents for future applications.