Least Bittern (Ixobrychus exilis)
The Least Bittern is the smallest heron found in the Western Hemisphere. It is normally shy, and when seen at all is usually at the edge of reeds or other vegetation, poised on the lookout for small fish, amphibians or crustaceans, and ready to fade back into cover at any disturbance. This is the only one I have ever seen walking around in the open. It was less than 20 feet away from several people, and remained exposed for two to three minutes.
Photographed at the Wakodahatchee Wetlands, Palm Beach County, FL