Great timing to capture this scene! I'll echo a few comments - with the horizontal lines in the background there is a definite need for a significant amount of CW rotation. There is a colour cast to the image - I might suggest going back to your RAW file and using the white balance eye-dropper on the brightest part of the plummage as a starting point and going from there. The lighting situation here looks tough - the sun appears to be almost directly overhead - you've done well given the conditions, but in future you might consider revisiting the location at a different time of day or using a bit fill flash to even out the lighting on the plummage.
I like the way you have caught the egret in flight - coming in to land. There are problems with the alignment of the image and the necessary rotation is going to mean rebuilding the top right of the image /background.
From what I have read, I suspect that the grey in the whites of the bird are from an over use of the "recovery" slider and the whites on the head of the bird still seem to lack detail, are a bit patchy.
My best advice would be to take a look at Robert O'Toole's APTATS II CD - I just did myself - and there is some excellent guidance there on dealing with whites in images like this.