Jail birds. I am continuing my project of taming these two feral kittens that were born in my cellar. They seem to enjoy the 8" X 16" foundation vent as a safe vantage point. They do have free access in and out of the cellar. On the inside there is a smooth concrete block wall. The kitties have to leap or scale several feet to get to the vent opening.
They will not let me catch them, but when I walk away, they will be right at my heels.