In Glacier I was so freaked out about the Grizzlies I rigged a trip wire all the way around my tent at night rigged to the motion detector alarm. I just had to remember it was out there in the middle of the night when I went to take a leak. Once a robin flew into the wire and set it off early in the morning (I had a big flock of them around the tent).

Not sure I would take that tack again. It certainly didn't deter my camp bear and who knows it could be counter productive. Maybe he/she would of just smelled around and left.