A little strange

Just to throw it out there, I don't believe in ghosts, spirits, or any of that stuff.  However... Ever since we've moved into this house, we've heard some strange noises, which we normally just blame on the 'newness' of the house, the wind or other elements, and we'll just get used to those subtle sounds. So really, nothing too crazy.

Today was slightly different. We came home, and the Christmas lights around our deck were on, which is normal. But we also have about half a dozen regular lights that were installed mainly for use in the summer.  In order to turn those on, you need to flip a switch outside, which is protected by an all-weather cover (similar to those covers that cover outdoor outlets). To our surprise, those lights were on! We haven't had those on in quite a while, and were quite surprised to see them on. Since there is snow on the ground, I went outside to see if there were any footprints. Perhaps one of the neighbour kids decided to turn them on? But no suck luck. The only prints that we saw (and that were in the direct neighbourhood of the switch), were prints of a squirrel. Now the question remains: do we really have a squirrel that is so thankful for all the bird food that we leave out, that it decided to turn on the lights for us? But if so, how was it able to lift the cover of the switch?
Or is there another explanation??