I hunt deer a lot and they are a pest! Doesn't matter if they are grey or red squirrels either. Not 5 minutes after I find a place to stand or sit, they start to squawk being ticked off. Just the other night I was long range scouting deer and a chipmunk and squirrel were making so much commotion 20 yards from me, it got the attention of a buck 300 yards away!
So my tip: Sneak along and sit where you think a squirrel or two may be at. Sit there for a few minutes after things have quieted down, and they'll go about their business.
iSnipe.