Use ultrasonic noises to deter crop damage by mammals to reduce human-wildlife conflict
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Ultrasonic noise is sound waves at higher frequencies than those audible to humans. Different mammal species can detect sound at different ranges of frequencies, so some ultrasonic noises may be audible to a range of mammal species. If ultrasonic noises can deter animals from damaging crops, this could reduce motivation for carrying out lethal control of such species.
See also: Use lights and sound to deter crop damage by mammals to reduce human-wildlife conflict, Use noise aversive conditioning to deter crop damage by mammals to reduce human-wildlife conflict and Use loud noises to deter crop damage (e.g. banger sticks, drums, tins, iron sheets) by mammals to reduce human-wildlife conflict.
Supporting evidence from individual studies
A replicated, controlled, paired sites study in 1995–1996 on a grassland site in Victoria, Australia (Bender 2003) found that ultrasonic devices (ROO-Guard) did not repel eastern gray kangaroos Macropus giganteus. The number of kangaroo faecal pellets counted with the devices running (0.36–0.38 pellets/m2/day) was not significantly different from the number counted in the presence of dummy devices (0.17–0.20 pellets/m2/day). ROO-Guards were reported by the manufacturer to emit high frequency noise that is inaudible to humans but which deters kangaroos by masking their ability to hear predators. ROO-Guard Mk II devices were operated in December 1995–January 1996 in five open grassy areas of ≥100 m diameter. Each was paired with a similar area ≥850 m away, where an inactive device was simultaneously placed. Kangaroo use of each area was assessed by counting faecal pellets after 5–10 days.Study and other actions tested