Nice light and feather detail Tom. It's always tough to get that head angle when the birds are preening - well done here! I agree that you might dodge that mark on the left (and perhaps the dark blue one on the right edge?). Perhaps a little tighter crop?
The light is showing off the nice sheen on the feathers, this species normally look a little dull, but you have brought out the best in it I think. Nicely composed in the frame I feel, and like the natural behavior
Wow, excellent preening pose, Tom, to get the head almost parallel to the sensor like that. I love how the eye is almost the same color as the water so it kinda looks like you're looking through a hole to the water beyond. Sweet light and colors.