Rat's eyes seem to be very sensitive to the slightest movement near their
level, but they don't appear to have much awareness of things above them.
So I bait a particular area below an upstairs window and zero the air
rifle for that distance. Choose a day when the wind is in your face.

Excatly what I did to rid my parents place of rats.

Dave

--
For what we are about to balls up may common sense prevent us doing it
again
in the future!!