Saw this a couple weeks ago and it wasn't that bad, now it has tripled in size. Can you tell what pest digs like this? I have seen a chipmunk in the yard but do they dig up along foundations?
you don't have gophers in WI, do you? moles usually do very little soil movement. their piles are quite small. voles?
Chipmunks holes, generally, do not have mounds of soil around them, don't know what they do with the soil excavated but it does not get put there. Perhaps the link below might be of some help.
Here is a link that might be useful: what makes mounds