Here are several references that show that ultrasound devices are not effective in controlling rodents.
Sprock, C.M., W.E. Howard, and F.C Jacob. 1967. Sound as a deterrent to
rats and mice. J. Wildl. Manage. 33194)724-736.
Howard, W.E., and R.E. Marsh. 1982. Ultrasonics and electromagnetic control of rodents. Third Intern. Theriological Congress, 15-20 August 1982, Helsinki, abstract.
Howard, W.E., and R.E. Marsh.1985. Ultrasonics and electromagnetic control of rodents. Acta Zool. Fennica 173:187-189.
EPA funded our electromagnetic study and we worked with EPA to help the Federal
Trade Commission try to ban ultrasonics. I think we demonstrated that the success
of a roent control program with ultrasonics was just as successful if the units
were not turned on. Unfortunately, since the
devices do not harm people the Federal Trade Commission could only prosecute sellers of the devices if they made false claims.
Rex Marsh and I had an experiment all ready to go with wild rats to show that
we could easily condition them to come to the location of an
ultrasonic device for food whenever they heard the device. To our
disappointment the FTC were not able to fund us.
Walter E. (Howdy) Howard
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