On Thu, Jul 20, 2006 at 09:10:08AM +0930, Tony Russell wrote:
> I had a quick look at this website and it would appear that CATWATCH
> does provide an effective deterrent for cats.
Amazing it does seem to have some effect. I've seen ultrasonic repellers
advertising as deterring cockroaches, mosquitos, mice, rats, dogs, foxes,
deer, kangaroos and a variety of birds. I've seen no reason to believe
any of them work and ins ome cases, e.g. birds, there a good reasons to
believe that don't work.
But people from the RSPB field tested the CatWatch device in a
controlled experiments (ref below). In one experiment it reduced
cat intrusions into gardens by 32% in the second experiment it had no
statistically-significant effect on intrusions. In both experiments it
reduced the time the cats were in the garden (by 38% & 22%).
Although the effect looks real but it also looks too small to be be of
great practical value. The maker claim a range of 7m and the device
will be much louder at few metres so maybe if you have a very small
area you want to deter cats from it could be useful.
The device produces loud ultrasound at 21-23khz. Loud enough to to
exceed occupational limits for humans if it operated continuouly - which
it doesn't - and you stood next to it for hours - which presumably
you won't. Human hearing sensitivity drops off sharply below this
frequency but I would of thought some (young) humans would be able to
hear the device. Cats have better high frequency hearing than us and
they'll certainly hear it.
The efficacy of an ultrasonic cat deterrent, Nelson et al, Applied Animal
Behaviour Science Volume 96, Issues 1-2 , January 2006, Pages 83-91
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