I dug (ha!) through the first 12 pages and didn't see this question. I noticed a large pile of dirt next to my front porch slab about 2 weeks ago and there was a 8-10" hole going under the slab. I tried flushing it out with some water (didn't work) and I started laying sponges soaked in ammonia that night. 5 ammonia soaked sponges have been removed by the animal in the two weeks since. Yesterday I moved the dirt pile, and whatever it is has excavated about 30 gallons of dirt and 1-2" rock. I also removed all ground cover and replaced with mulch. I then put down some pepper deterrent. I think I've narrowed it down to skunk, raccoon, or woodchuck.
I thought of spraying the yard for grubs but I don't really notice any activity. I'm in Illinois so I can't trap/remove myself, and animal control in my city won't assist unless it is IN the house (slabs, window wells, etc. don't count). Firearms won't work because I'm in the city and wife wouldn't allow it. Poison is also out of the question because that is also illegal and even if it wasn't, I've got pets. Now that I've eliminated most popular recommendations

, any other ideas on how to get rid of this thing?