behind a window is fine, a little slower but at least the birds arent going to have expensive nesting materials. i usually have mine behind a window but outside when im home.doing that.. but behind a window... can only try to do the windowsill when i am home due to the pesky birds.. I think my rangeman spent 11 months in a closed box on M
if youre ranger has been out of action that long then its probably sitting just above L. def. needs a good long drink!