Any idea how to get rid of a pest cat?  One has been terrorizing our yard
on-and-off for three years now, and we're at wits end!  Specifically, it
scratches up our garden mulch and pees and craps in our yard--putting kill
spots everywhere.

We've tried:
- Bought a motion-sensitive sprinkler head.  It quickly turns on and shoots
water around a radius when it detects motion.  All this did was teach the
cat the coverage area of the sprinkler; he did his business outside the
radius.
- Put chicken wire under the garden mulch.  The theory is it catches his
claws and deters him.  Didn't work.
- Put down bloodmeal along the perimeter of the yard (which is already
fenced).  This works somewhat but is expensive and time consuming.
- Baited a live trap with various cat food, tuna, chicken bones, etc.  He
won't go into it.

We recently bought a waterproof security camera to monitor the area in an
attempt to find his "pattern," but this is extraordinarily time consuming.
Fast forwarding through hours of videotape each day is a waste of our
precious time.  (I could use the camera's motion-sensitive VCR controller to
limit the recording to motion-activated shots, but it does not overlay a
time stamp so we won't know what time he came by.)

My wife is ready to sit outside all day and all night and shoot this damn
thing.  She's spent a lot of time, money, and energy maintaining a beautiful
yard and is tired of spending as much resources fighting this cat.

Yes, we know it's a cat.  We've seen it jump over our fence and going in and
out of other people's yards and the pee stains are long, deliberate spray
marks.  It is not a neighborhood cat; it is a stray.