American Bitterns typically nest in tall, standing cattails, rushes and sedges, where they are well concealed. Like most birds, male bitterns use their voice to attract a female and to stake out their territory. Dense marshes present a challenge when it comes to being heard, however. American Bitterns overcome this challenge by having a very low-frequency call, which is audible at great distances in dense marsh vegetation. Once you’ve heard a bittern’s call, you’ll never forget it. It is very deep, and has three syllables – “oong-ka-choonk” – which are preceded by clicks and gulps. The bittern makes this call multiple times by inflating his esophagus while contorting himself quite violently. A female American Bittern couldn’t help but be impressed. (You can hear a bittern calling by visiting Cornell’s site, http://www.allaboutbirds.org/guide/american_bittern/sounds .