I met several other experienced photographers and together we tried various settings and talked out problems. We even tried different cameras to rule out an issue with the camera I was using with was a Canon 5D Mk III.
My first thoughts were to increase tracking sensitivity, Frustration on missed shots began immediately. One of the gentlemen shooting with us said it should be reversed from what I was thinking. I moved the tracking sensitivity to zero. Better but still no cigar. The lens still seemed to lose focus easily and began hunting. I moved the lever from the full to the 15m to infinity position. Huge difference. Next I changed the AF point from single to area. Another improvement. After that the recommendation was made to change to back focus. A bit of getting use to but I think I will like it and it seemed to help in more quickly establishing focus on a moving bird.
By the end of the day, there was improvement from the first shots of the day. I can only speak from personal experience but I still find that the lens is slow to focus, even in good light. Hopefully with some additional tweaking and practice, I can nail down the idiosyncrasies of this lens. At this point I am not sure that it will be a successful lens for wing shots. The recommendation was made to try on a camera with a cropped sensor. My next go round out I will take my Canon 7D out and give it a go on that one.
I am still pleased with the Tamron for still, portrait type shots but I am beginning to wonder if it is going to be successful for wing shots. I am hope some additional tweaking and practice will prove it useful for those. At this time the focus still seems very slow resulting in blurred shots for moving birds. It is definitely not a slap on you camera lens and expect peak performance.