Good light, actually it was a dull light that helped capture the details of this birds feathers.
It’s not common to photograph the full details of a pure white birds feather structure. Pure White, and black, are outside the color range of a camera. Film too for that matter. There was a time I knew the ranges, the 255 different shades, etc. I learned just enough tricks to shoot white birds. Only so much room in my head.

Great Egret posing on a nest.