Late last winter I looked out of our lakeside windows and watched a lone coyote trotting along on the ice. Where he came from, I don't know but I watched as he made his way over to Sleepers Island. He went up onto the island at the Alton end. So you might have at least one coyote out there.
Personally, I would never use a baseball bat on a coyote. If he got that close, he would definitely be sick (rabies?) and I'm not about to go through those nasty shots. A trusty .38 special in the pocket (properly permitted, of course) would work for me. The noise alone would probably scare it off (and half of the residents as well).