Nikon 70-200 2.8 with a TC2.0 VIII is not very good on my D800

Are some not looking at the picture detail?

I presume they OP wanted the head to be sharp - it is not

If this is what the OP is unhappy with; the problem is the subject. The far wing has good contrast and good detail and is the best autofocus subject. The body outline is small in the frame and low contrast and the wing closest to the camera has no contrast.

The autofocus appears to have worked as it designed to work by focusing on the best area of contrast. This may not be what was wanted. If so my advice is try again in different lighting conditions.

For side on shots such as this a small aperture of f8 or f11 would better handle the depth of field needed to get both wingtips sharp.

--

Leonard Shepherd
Many problems turn out to be a lack of intimate knowledge of complex modern camera equipment.