On Mon, 14 Jan 2008 21:41:50 +0000, Maxine G wrote:

Raccoons getting into cat doors are a big problem around here. Maybe we
just need to accept frequent replacement of collars.

Been there, solved the problem. I have 15 cats and live in raccoon and
possum teritory. I used to have to chase them out nearly every night - I
even found a possum taking a nap in my computer room. The only varmin
that got inside in the last year was a coon that came in one night I left
the back door open too long. The cats, all but the oldest (very frail)
come and go at will through the new cat flap.

The secret is not the design of the cat flap or some special recognition
device, it's the placement of the flap: if the platform outside the flap
requires a leap of three feet or so to reach, cats have no problem but
raccoons and possums can't leap, and therefore can't reach the platform.
It has to be constructed so that the vermin can't reach it by climbing.

In this picture (http://67.54.246.139:9000/tdavis/cats/cat_flap.jpg),
Tigger is on the platform for the vermin proof version - the hole next to
the bottom of the door is the old one and has been blocked off.

It would be practical to put one in a window - just watch the length of
the leap and provide a reasonable platform for landing in both directions
(mine are the top step and the shelf.

--

T.E.D. ) MST (Missouri University of Science and Technology)
used to be UMR (University of Missouri - Rolla).