I also vote for the Raccoon. As another Pacific Northwesterner - I have seen these vistors in my back yard.

The best way to describe them is that they behave like a pack of juvenile delinquents - tipping things over, muddying up the water... I can always tell when a raccoon has used my cats' outdoor water dish.

One time my next-door neighbor left a plastic container of cat food outside, we found it the next day in our yard, with a hole chewed through it. Also, because they need water, our sprinker hose that was lying on a new patch of lawn was chewed and rearranged