Also, for interest's sake, the tooth marks on the nuts will tell you if there's more than one species eating them. You never know, you may have dormice for neighbours. *the super cute hazel/common one.
Squirrel prob. Something big just chomping through them. Dormouse chewed nuts have teeth marks going in rings around the hole. Woodmouse/vole chewed things have teeth marks going straight into, and all around the hole, with some differences between the two which I forget right now.
Also, for interest's sake, the tooth marks on the nuts will tell you if there's more than one species eating them. You never know, you may have dormice for neighbours. *the super cute hazel/common one.