Stocky, brown heron found in marshes and bogs. Usually secretive and difficult to see, but occasionally found in the open. Most similar to juvenile night-herons. Note striped neck, plain unspotted wings, and even more secretive behavior of bittern. Most active around dawn and dusk, when it might be seen flying low over extensive marshes. Listen for its incredible vocalization in the spring and summer: a resonant, booming noise produced by air sacs on the neck, “oonk-GA-loonk.” Also gives single low squawks.