I have used black pepper with pretty good results. Since it takes a lot to cover a whol lawn, I buy at the wholesale place, and pepper a perimeter fairly heavily, and a lighter sprinkle over the rest of the yard. Works for a week to two, or so it seems. I haven't tried the citrus peel, but I know the cats have never deposited under my lemon tree. I sure like the motion detector idea! that might be good for badguys too. My mailman would probably make me eat my mail the first time he forgot it was out there! He always cuts across the lawn! Reminds me of my old apartment manager, who would threaten to evict me because he would come in to change a washer on the tub faucet, and forget to turn the shower lever before he turned the water on! He always had his head under the shower! Ha! I told him he shouldn't use such cheap washers and he wouldn't have to get wet so often.
SJ

Tell me about it (human vs cat as forces of destruction). As if humans already didn't have a taste for the strangest things... Ever eaten a robin? (They're small, pretty yummy, but hardly worth the bother for all them little bones.) Snails? (Dig them out of the shells!) Beetles? (Taste like chicken, they really do!) Ants? I can see eating ants, especially the ones with stinging bites -- just like picante!

A neighbour of mine built a pond, and put fish in it. Then he complained about the grey heron eating his fish. Tsk. You want to live next door to a conservation area, you can't pick and choose your wildlife.

Right now, the chicken wire pea trellises are protecting the moss from the dark side of the Paws, and the back end of the Force, and I've got two Hallowe'en bales of straw on my garden to protect it from the marauding meows until the snow comes. (And to protect the two Oxheart carrots I managed to resist eating so I could have seeds next year!) I'll try the citrus peelings in the rest of the garden, though, to ward off the Russian Blues in the spring.

Is there anything I should know about what the peelings will do to the really yummy soil I cooked up over the last two years, or can I just be my tra-la-la carefree self in planting whatever seems to work?

I don't think the peelings will do anything to your lovely soil so you can tra-la-la away. Citrus peelings usually take quite a while to decompose in my compost pile so they will probably just sit there and smell funny until the worms and micro-herd do their job of breaking them down.

If anything, I would think they would be slightly acidic but I've never heard of using citrus peel for azaleas so they can't be too strong.

Go for it!