It can be Chip Monks or Squirrels.

Birds can do that too.

Chipmunks....

My various little lizards also do it.

Dave

Birds can make holes searching for insects. Toads will dig burrows in soft ground to hide from the sun. Mole crickets also dig burrows. It might be worthwhile to gently dig in & around several of the holes to see if anything is still there.

Maybe voles? (field mice)

Chipmunks and voles do it here. I have holes just like that all over my property.

Skunks do it as well - their holes are usually deeper and wider, but I see them sometime from my window starting to dig and move to another spot, leaving holes like on the picture.

Thanks for all the inputs. So far it was done only on one day so its OK. I will try and see if I can catch any intruder early morning or late evening! Appreciate all your inputs,

Just about a week ago, I was visiting a friend. I saw a pot that wad dug just like that. Lo and behold, few minutes later a chipmonk came started doing it in front of our eyes. We covered the pots with chicken wire.

Those hole are two big for birds and too small for things like skunk , raccoon.

Yes darn those chipmunks!! There's one I think that eats my strawberries every morning. He is always near my strawberry plants. Some of them look obese due to the amount of things they eat from our garden :-]