Kirk, I am convinced that turkeys absolutely can pick up bright colors, even if only the one on your bow. When I first started trying to hunt turkeys without a blind I used bright fletch and kept getting busted everytime they got close. I use flo. orange for all my hunting except turkeys. For those, it's natural barred or natural colors only. It does seem to have helped.
I know that Joebuck is so concerned about turkeys sight that he colors his steel broadheads with a black magic maker. They have excellent vision!
That being said, I have had turkeys walk right by me during deer gun season while wear blaze orange and they never even looked my way. Go figure.