Soak a rag in white vinegar and hang it in the area, preferably in the path a critter would travel. You can protect it from being diluted by rain, etc., by hanging it like a bell clapper under a plastic jug that you cut the bottom out of and suspend that in the path. Critters make their living with their noses and cheap vinegar stinks to them, and more importantly dominates the air which will screw up their ability to detect ordinary aromas. Like Chickenshit, fish offal, and whatever else you organic freaks use. Bone appetite! (Vinegar is a herbicide, so be aware)