Introduction

Adult male American Bittern displaying white shoulder plumes, NY, May

Fig. 1. Distribution of the American Bittern.

The American Bittern is a solitary, cryptically colored heron that breeds in freshwater wetlands from the mid-United States to northern Canada. It prefers wetlands dominated by tall, emergent vegetation, and within these habitats frequents vegetation fringes and shorelines. It relies on stealth more than pursuit to forage, waiting motionless for long periods to capture passing prey—mainly insects, amphibians, crayfish, and small fish and mammals. It is most active during crepuscular hours.

This bittern uses resounding calls to communicate within the thick vegetation that dominates its nesting habitats. These calls have an eerie, ventriloquistic quality, and many vernacular names for this species, including “stake-driver,” “thunder-pumper,” and “mire-drum,” alludes to these calls. Males use elaborate displays to court females but participate little in rearing the young. Females build nests; incubate eggs, and feed and brood chicks.

Because of this species’ secretive nature and inaccessible habitats, remarkably little is known about basic aspects of its biology, including sources of mortality, habitat use, mating systems, and population structure. Basic research on its natural history would help to conserve the species, which is undergoing substantial declines over much of the U.S. owing largely to loss and degradation of wetland habitats.