Start with a mousetrap....I don't know what the heck you got there, but if those are mouse turds, he's full of shit!!! I'd get some kind of no pest strip in there asap for the flying things. If it's a mouse you should catch him...I get mice in my grow room every now and then...they seem to like to dig in the soil. I just set a trap baited with peanut butter and kill them. Good luck, Tevfic!