I’ve only used this lens on two outings, and with hindsight I realize I was asking a lot of it. I plumped for lower ISO and therefore slower shutter speeds in the belief or hope that the VR – vibration reduction – would cope with everything. But of course it cannot deal with subject movement, and one of the things I found after reviewing shots of some birds is that they move. When pecking and walking, they move. And a slow shutter speed takes the edge off the sharpness of the shot.
I can tell from the nature of the blur that it is not camera shake but subject movement that is the problem.
Here this bird was obliging enough not to be moving.