You guys are making it sound like you can't even blink without him seeing it. I can attest that you CAN move on a bird-- but the movement has to be IMPERCETABLY SLOW!! On two different kills and many other occaisions, I have had to move <u>a long way</u> and have gotten away with it. Once I had a whole flock of hens swarm all around me, comming on the run, when I changed from yelping at a hung-up tom to a feeding purr. One hen was no more than 15 feet from me when the tom showed. I had to put down my slate and reach for my shotgun, then shoulder it and fire. Not one of those birds knew I was there until I pulled the trigger. I got caught flatfooted that morning, but I simply moved VERY slow and took my time. I figured that if I got the shot, great, but if I ran out of time... well that's better than spooking him. Another morning, I had a 2-year-old to fly into a tree about 30 feet behind me while calling. I was trying to locate a bird to set up on when he came flapping in. I did the same thing-- moved VERY slow to pocket my box and raised my shotgun.
Now, I'm not saying that these aren't some of the sharpest eyes around, but they can be fooled. You just have to move about as fast as the shadows move across the forest floor and be very careful how you move your head.
Now, having said all that, I will agree that it is best to be waiting for him than chasing him. Bobgobble2 describes the perfect setup and when everything else falls into place, its pure poetry. But just because he circles or comes in from your right or something, don't give up. And don't lose patience.
Ya'll don't forget to have fun out there!

And Huntma, watch out for them bears!