Upper Midwest Environmental Sciences Center
Custer, T. W., 2000, Environmental contaminants, Kushlna, J. A., and Hafner, H., eds., Heron Conservation: San Diego, Academic Press, p. 251-267.
Throughout the world, individuals and populations of herons are affected by environmental contaminants, leading to direct mortality, decreased reproductive success, or degradation of feeding habitat. Contaminants suspected or known to affect herons include organochlorine compounds, organophosphorus insecticides, trace elements, and petroleum (Parnell et al. 1988). General reviews on the effects of pesticides on birds (Risebrough 1986, 1991) and colonial water birds (Nisbet 1980) are presented elsewhere. The objective of this chapter is to review toxic effects of contaminants on herons. Unless otherwise noted, contaminant concentrations are presented as parts per million (ppm) on a wet weight (ww) basis.
Black-crowned Night Herons, organochlorine insecticides, dieldrin, Eggshell thinning, PCBs, dioxins, Mercury concentrations