Living in the middle of nowhere, I've had my share of coyote misery. Just a couple of months ago, on my way home from work around midnight (riding my bicycle through the woods), I had a standoff with a coyote. It was pretty neat. I know this sounds completely crazy, but in order to keep the coyotes away from my yard, I pee in the yard as often as I can. I hardly ever use the real bathroom in summertime. It does help to keep the wild animals away.
Oh and something else that works great.. (I am serious). Go to the zoo and ask for some lion poop. The last zoo where I picked up lion poop, I had to pay for it (4 dollar for 20 pounds). The "wild animal" smell will keep smaller wild animals away. It really works, I swear.