Heard a Noise

So I heard a noise outside, looked out my window, and didn't see anything. A few minutes later, I heard it again, like a scratching sound, and checked outside. Nothing.

And then I heard it again, and went outside, and it was really cold and some dog was out in the front yard. It saw me, barked and then ran off.

I went back inside and was bothered by no more noises.