What's that scratching sound?

Since the weather started getting cold we have heard an occasion scratching on the roof in the middle of the night. I was afraid that we had some kind of rodent in the atic. I crawled up there, but it was nice and empty. This last week the weather was much colder (It even snowed her last Monday), and the scratching was happening every night. Today I finally had an opportunity to investigate the source of the sound. Our house has a covering over the eves (you can see it in the pictures below). It makes it look nice. There is a problem with this covering. It creates a small tunnel under the eves, and it is not sealed off. There is an opening by our patio cover. Well I think I will let the pictues do the rest of the talking.