I recently saw a heron/egret I couldn't identify....   It was walking in
the edge of the surf, it looked like a Great Egret (and I had seen
several in the neighborhood), but it was all gray.  It was very tall,
slim, graceful, the legs and bill grayish.  It didn't have the shape of
a GBHeron.  It tucked it's neck when it flew.

(Whisper:  I was in Port Aransas. )

Checked several books and can't come up with a juvenile bird that fits.
Any ideas?