Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable
Comments: Past decline of the U.S. population is attributed to prairie cultivation, wetland drainage, logging of forests, egg collecting, and indiscriminate shooting (Cely 1979, Meyer 1990, Meyer 1995).
Habitat alteration and loss continue at an accelerated pace in the United States. In Florida, most nesting and roosting habitat occurs on private land which is being converted to large-scale agriculture operations. Short-rotation, even-aged pine plantations reduce the number of tall, emergent trees required for nesting. Poor fire management can reduce habitat heterogeneity or reduce the number of nesting or roosting trees (Meyer and Collopy 1995). Threats along migration routes and on the winter range are unknown (Meyer and Collopy 1996).
Low (non-lethal) concentrations of mercury were found in tissues of two nestlings and three adults collected in Florida (Lee and Clark 1993, Meyer 1995). The significance of this as a threat is unknown.