OK.... something else I'll try. I have been using center point with and without 4 and 8 point expansion for almost all my shots. I haven't bothered with zone or 65 points at all. In fact, I had them turned off so I'd have less choices to go through on AF selection.
I'll try 65 points with larger birds next time we have a non rainy, non work day. With iTR AF enable, as well, of course.
Kim (the male variety) Canon 1DX2 | 1D IV | 16-35 f/4 IS | 24-105 f/4 IS | 100L IS macro | 70-200mm f/2.8L IS II | 100-400Lii | 50 f/1.8 STM | Canon 1.4X III
RRS tripod and monopod | 580EXII | Cinch 1 & Loop 3 Special Edition | Editing Encouraged