The whites look very natural here and I love the upside-down preening action. Glad you sat long enough for it to do something besides stand and fish. Maybe a touch more contrast on the bird’s face would bring up some detail there. Not too much since the overall vibe is soft and gentle, but a little crispness could improve an already terrific shot.
Lovely catch!! And with the eye open! I love the pose, but wonder if the color cast is consistent with the cloudy lighting? Certainly possible, but for comparison here is a version with the whites neutralized (using the neutral eyedropper in Curves) then that layer reduced in opacity just a bit. Also did a brushed on soft-edged quick mask and made a masked Curves to lighten the face a bit and increase its contrast just a bit.
Thank you all for commenting with great suggestions. I had heaps of trouble with the colour cast. I think the yellowish cast in the shadow has come about from reflection off the rocks. I have lightened the face but will do so again.
Thanks Diane for taking the time to experiment! I will play some more.