Great Egrets are rather magnificent and getting really close to them can make you
a bit shaky. I sometimes deliberately slow my breathing in order to relax. If you
have a subject with bright plumage then your exposure might be off. For birds
you might try center-weighted exposure. White plumage may require some iris
compensation to the left to capture white detail even if the surrounding part
of the frame ends up under-exposed. Egrets are hard. They certainly seem to
be fine with you in the vicinity.