Ozzy is listening to the neighbor's Beagles baying in the distance. Usually these Beagles break loose from their electric fence, (taking the shock), to go charging after rabbits.
Ozzy isn't allowed to chase any animal, so the rabbits hide in our backyard. When we go outside, the rabbits don't even move out of the way anymore, so trusting they are of Ozzy not chasing them. Good thing he isn't a Beagle.