I realize that there is always a temptation to find success for
difficult problems in simple solutions, but there is virtually no
evidence  that ultrasonic rodent deterrent devices have any longterm
effect. In one study (Meehan 1984) 20 different devices were used in
field and lab tests -- none had any effect beyond a day, after which
time the rodents overcame any concern with the sound. There was no
improvement when the sound was variable, random, or intermittent.
Another study by Lund (in 1988) found the same thing, this time using 11
different devices.

The same can be said for use of these devices for birds.

Simply put -- and in spite of anecdotal comments -- these things don't
work, never have, and probably never will. If you have rodent problems
deal with them by cleaning (eliminating food and water), excluding
(eliminating access), and trapping (not poisoning). It's not easy, but
it works.

Best,

Michael Trinkley, Ph.D.
Director
Chicora Foundation, Inc.
PO Box 8664
Columbia, SC  29202
803/787-6910
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