I do know that raccons poop piles....and go back time and again to the same spot time and again building in time a mountain of racoon poop....but I think you would know the difference!!
I often find piles ( little piles!) of chipmunk poop on top of a light on my deck....but I often see them eating their acorns from that perch.
Could it be that a mouse got trapped in there....or could it be dead bugs?
Linda C

Deer do also, but I think you would probably know if you had one in your house.

Not in the same house anymore, but from experience ... mice also like paper, could there have been a piece of paper there? Or perhaps they got a piece of food somewhere else and carried it to their safe spot?

"Our" mice once found a nice spot in a linen closet - no food but not reachable by our terriers. I actually think the field mice are kind of cute, but I am very afraid of them - it's the being startled aspect that bothers me the most. Also the hygiene aspect. It still gives me shivers thinking of when I opened the linen closet door.
Good luck.

I don't know why anyone would PREFER it to be mouse poop.....I, too,grew up w/ mice as part of country life .... and THEN someone invented HANTA VIRUS - and nothing - not even mouse poop was quite the same - whether in piles or scattered like leaves . Be very careful how you clean up mouse poop ....

Vicki

Look directly up from the pile. Is there a place in the window that a bat could be roosting? Perhaps between the storm and the window? Or something like that? Bats poop in piles underneath their roost sites, and if you're in an old house, it's possible one could find a cozy little niche to get into from outside.

Good idea, JenswrensÂthanks! The droppings looked a little smaller than bat guano to me, but I grabbed a flashlight and checked thoroughly. No bats. I would have been surprised if there had been one, though, because the bedroom was recently remodeled, and the windows are new. The mystery remains a mystery...