Protocol for Field Tests of Ultrasonic Devices for Rodent Management

Abstract

Testing ultrasonic devices for rodent repellency in closed environments results in contradictory responses. Without alternative environments, such efficacy tests cannot approximate actual conditions, and can result in erroneous conclusions. Conducting observations in actual rodent-infested environments provides the best circumstances in which to measure the efficacy of high-frequency sound as a rodent management tool. Ideally, the installation of ultrasonic devices should be the only environmental variable. Rodent activity, measured with tracking patches, food consumption, or motion monitors before and after activation of units, is correlated with sound pressure patterns in the environment. Both frequency and sound pressure are important parameters. Preferably, two on/off cycles should be used.

Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?

“…Commercial ultrasonic units fall below this threshold; most units do not operate continuously, and sound pressures (except very close to the transducers) are less than 120 dB. Some workers, especially younger females, may be annoyed by the ultrasound field' [66] (noting that these stated dB levels are re 20 µPa RMS). Recent measurements in a Tokyo restaurant detected 120 dB re 20 µPa SPL directly under a pest deterrent source, and 90 dB re 20 µPa SPL some 15 m from it, and noted strong adverse reactions from some people, §3b(iii) (1).…”