WOW! THANK YOU!!! That's great! I was shocked to see the picture. I would never have guessed that in a million years. I think you are right!!! Yeah! :) So, that explains how these piles disappear after it rains. Its just a pile of dirt. My only question relates to the size. The pic you linked to doesn't have a discernable reference as those grass leaves could be any size. So since there is this size reference issue in the photo that you linked to, I will e-mail Walter Reeves at his site just to verify that the stuff in my yard is the right size for it to be these earthworm castings. It sure does look like it from the pic. I am so happy that's all it is! THANK YOU SO VERY MUCH!!!!

I am thinking that the following may help with what it is not: Human http://courses.washington.edu/chordate/453photos/skeleton_photos/human_vert.jpg Dolphin http://courses.washington.edu/chordate/453photos/skeleton_photos/dolphin_vertebrae.jpg Horse http://courses.washington.edu/chordate/453photos/skeleton_photos/lumbar_vert_anterior.jpg Here is a link that might be useful: Biology 453 Amniote Skeleton Photos

We did look at the ledge during the day when we took this picture, but there is nothing above it except for the overhang. The only place they could be hanging out is right on the ledge. We've noticed a few scattered droppings on the floor of our porch that appear to have fallen off, but we've cleaned them up and there isn't any fresh droppings for several days and then they appear again. Whatever is hanging out, seems to come and go.

No. It's not from someone in the household. We don't have anyone in the house with that small a handprint. In addition, these prints are all over the glass panes, from the very bottom to the top, some are overlapping. It's hard to take a picture showing that but these prints filled the entire glass surface from repeated trips up.