I believe this is a juvenile heron. No crown, no neck dress, and quite a bit shorter than an adult.
I could get up quite close before it flew away.

It was getting very dark by this time. A good test for the tele lens. It all happened so fast, all I remembered another Olympus user say f 8.o is the sweet spot for sharp shots with this lens.

I am open to suggestions from other mirror less users.