^^^^
Viewed on latest Safari on my Mac, there is a bluish tinge to some parts but the wing's secondary feathers are pure white and any blue is tending to look like blue sky reflections on the water.
But Rich is right: All photography is a balance between aperture and speed, with ISO rating thrown in to help it where needed. So, in this case, you can afford to reduce some of your settings in order to achieve a better balance. Each setting delivers different properties.
You're doing very well, PND, in my opinion and it's more important to get the shot and enjoy it.