The Problem With Flies

For some reason, the window in our garage suddenly became swarmed with flies. It's a little hard to see in the pictures, but there is clearly more than just a few stragglers who accidentally flew into the garage. Nick sprayed the window and now there are fly carcasses everywhere. Hopefully we figure out where they are coming from. Maybe one layed eggs on the window, they hatched, and then were trapped behind the blinds?

Update: We think it was keeping the stinky diapers in the garbage bin in the garage. Moved the bin and problem solved.