Beautiful, Glenn.
Does the sharpness of the tail have to do with it falling out of the focal plane, or is it a softness of the edge of the lens you are using?
I don't think it detracts from the image at all, but I am just curious.
It is a DOF issue. Shooting wide open with that much lens you have a very shallow DOF (especially when very close to the subject).
Cheers!