The primary reason for the decline in American bittern populations is loss of habitat. The marshes and swamps upon which this species depends have been drained and filled for a variety of human uses including roadways, housing and commercial developments. The American bittern was common in Connecticut during the late 1800s and it was a regular, but not abundant, resident of freshwater wetlands in the early 1900s. It is currently considered a rare migrant and uncommon nester, with only one confirmed Connecticut breeding location reported in the last decade. The American bittern, like many other herons, is solitary and moves slowly and secretively through dense marsh vegetation.
Bitterns are most active at dusk and through the night.
If alarmed, a bittern will stand motionless with its bill pointed straight up and its body contracted. Bitterns call most often in the spring. This unique call has led to many other common names, including water-belcher, mire drum and thunder pumper. During the breeding season, the males perform a remarkable courtship walk displaying white fan-like ruffs raised over their back and shoulders. State - Connecticut General Statutes Sec.