Analysis and effectiveness of deer whistles for motor vehicles: frequencies, levels, and animal threshold responses

Whitetail deer (Odocileus virginianus) are common across much of the United States. In areas where deer populations are prevalent, there is a propensity for interactions with automobiles. Various methods have been suggested for reducing the number of automobile-deer collisions, including acoustic devices such as deer whistles. Six different whistles were tested in the laboratory and on motor vehicles. Frequencies and intensities generated by the devices when mounted on vehicles at speeds from 30–45 miles per hour were determined. The primary frequency of operation of the closed end whistles on vehicles was determined to be approximately 3.3 kHz with little variation with changes in air pressure. Open-end whistles had a primary frequency of about 12 kHz, with significant variation with changes in air pressure. The best frequency range of hearing for whitetail deer appears to be between 2 and 6 kHz. The effectiveness of these devices was concluded based on the comparison of the acoustical attributes of the devices to deer hearing thresholds and acoustic behavior.