Sudden flurry of holes in flower garden
We have a flower garden installed where a tree was cut down 12 years ago. We'd removed most of the chippings and put in dirt, but the nearby yard has decaying roots. Two days ago there were several new holes, mostly about two inches across. We know we have mice, voles and young rabbits in the yard. Also at least one toad. What could have dug the new holes? We live in Talleyville.
New Castle County Delaware
Actually, it's possible that the holes are occurring because roots from your long-ago tree have finally rotted and the soil has collapsed into the void underground. I don't think any of the animals you named would dig a 2-inch hole. Squirrels dig shallow holes when they look for food they buried earlier. You didn't mention how deep the holes are. I hope you can solve this mystery!
You do have an interesting mystery. I would agree that the linear holes were probably made by voles. That smooth entrance around the two on the right looks like rodent holes, and a 2 inch diameter would indicate a larger animal, so rats could be the answer. Since they are nocturnal, it is unlikely you will see them, but the Warfarin should be effective. It may take several applications. Please use it with care.