Thanks Bryan and Gordon!
Virginia:
These were part of a sequence I shot very late in the day as the sun was going down, and I had bumped up the ISO to 800 in an effort to get some shutter speed. Was using the 300 f/4 + TC-14 combo wide open at f/5.6, so all of that combined to make them a bit soft and noisy. Plus, most of my shots that afternoon were either back- or front-focused (I think I have the same issue with my D2x Jim F. has been talking about). Because of all that, I had pretty much written off that sequence, but decided to go back through them to see if there were any I could salvage.
Thanks for the kind words...