Whilst visiting "our" kestrel the other day taking photos, I decided to have a look at the detail of some of the shots. Here is one from that day:
D800E + 300mm f2.8 VRII @ f5, 1/1250sec, ISO140 handheld minimal post processing
Best viewed at maximum by clicking on the images
Crop of above. If you look hard into the eye, you can see the clouds and possibly even me with a light coloured shirt on just to the left of the pupil.