In my garden, with freshly turned soil, these small holes keep showing up. About the size of a dime, and perfectly round. I dug a few up to see if there was any pest or further tunnel, but there does not seem to be any critter or tunnel. My best guess is some birds pecking for worms... but there are no bird foot prints in the surrounding loose soil, and they seem to be happening over night or in the very early morning.
And the perfect circular shape seems artificial...
And the perfect circular shape seems artificial...