I think the nikon camera setting was a good starting point and a good suggestion for a guided starting point. If you compare it to as shot it removes a lot of the cast strait away and then if you color picker on the white you can further tweak with the mired slider…given all that grass (bounce light) and the tinge that birds usually have on white plumage absolutely pure white is not likely an accurate reflection of what it should be but this can be tuned to the eye of the beholder… 