Green Heron (Butorides virescens)
A short stocky member of the Heron family which usually stands on the bank, a rock or perches on a low tree branch to hunt.
Because of the short legs when it hunts in the water it prefers shallow water with a rocky or sand bottom.
I often see them gliding with almost no wing flapping except to regain speed. They like wooded or brushy bodies of water and nest in thick areas of brush on shore.
From a slight distance they look all dark but up close or with good light they are pretty colorful with shades of dark green, reddish brown, yellow feet etc.

6D, 100-400L mk1 @ 285, 1/2599 @ f/8.0 ISO-4000
hand held at about 25 yards, back lighting by early afternoon light. I had been doing ducks up close when I saw it come cruising south bound and snapped off a burst as I tracked it past me. I never changed the zoom so this is a radical crop - redone in my new software from the OOC.