Minnesota Profile: American Bittern (Botaurus lentiginosus)
This mid-sized heron has a short neck and short legs. It is distinguished by a black patch on each side of its neck.
It breeds in central North America, from the East Coast almost to the West Coast, and the Great Plains and Ohio River north to Hudson Bay and Great Slave Lake. It overwinters in southern United States and Mexico.
When frightened, the bittern stands tall and points its bill skyward, relying on its striped breast to hide. It may sway with the wind. In this pose, the bittern can still look forward for danger. John James Audubon reported that "when I have suddenly come upon them, they have stood still from mere terror, until I have knocked them down with an oar or a stick." He noted that they are graceless fliers: "Their movements were so sluggish as to give opportunities of easily shooting them."
The bittern stalks the fringes of shallow wetlands, suddenly striking with its beak. It eats most any creature of suitable size, including dragonflies, various water bugs and fish, grasshoppers, crayfish, frogs, snakes, and small mammals such as meadow voles.
The female builds a nest of reeds and cattails, lined with fine grass. She lays two to seven eggs in early to mid-May. Eggs hatch after nearly a month. Young remain in the nest for two weeks and hang around to be fed for two weeks more.
The male's resounding breeding call of pump-er-lunk sounds more mechanical than biological and has earned it nicknames such as thunder-pumper, slough-pumper, and stake-driver.
Owing to their strange calls and penchant for "desolate" wetlands, bitterns were associated with evil. Author C.H. Merriam reported that 100 men in a Connecticut town gathered one Sunday in 1786 to rid nearby swamps of bitterns.
U.S. numbers of this nongame species are declining, probably due to the loss of wetlands through drainage and degradation such as siltation and pesticide contamination. In Minnesota, researchers use mirrors and recordings to lure males into live-traps. They band the captured birds with satellite transmitters to track them to Gulf Coast breeding grounds.
Where to See
Elusive and unevenly distributed, bitterns are hard to spot. Look in cattail marshes and other wetlands. An excellent site is the Agassiz National Wildlife Refuge in northwestern Minnesota.