Let's play 'What made these holes?'

[haruka]

There has been evidence of digging in my yard and I'm not sure what's doing it. Most of these are near my bird feeders, which are right next to the woods with the river down the hill.

( Pics and details under cut )

There's no shortage of wildlife around here. Even though we've only lived here since August, I've seen raccoons that were coming every night for a while, but haven't been around in about a month. My wife saw a skunk one night when the garbage was out. I saw a mouse, but haven't seen it again since we put the sonic device and a lot of peppermint oil under our house. There has been at least one squirrel, and a chipmunk, but we haven't seen the latter since around the same time the raccoons left. There's a stray cat that I've seen during the day. Also, there's been a coyote in the neighbourhood, but I haven't seen him personally.

I don't know if what's doing this is any of those, something else entirely, or several different animals. I've never caught any of these animals digging, the holes just seem to appear overnight.