Thanks guys! After posting I found some indication in a bird book that the western ones seem to be a little different. (As is everything else out here...)
Need to go back and hang out here with the 600 + 2X -- not a way to get closer to this tall tree. This was the 400 DO II + 2X. And haven't had time to do a microfocus adjustment yet. It looks like it's front-focusing a little.