Like all birds dependent on freshwater and marine wetlands, members of the heron family are suffering progressive loss of essential habitat. In addition, agricultural and industrial pollution threatens their capacity to reproduce. Great Blue Herons (Ardea herodias) and Black-crowned Night-Herons (Nycticorax nycticorax) have declined in parts of their range and have been placed on the National Audubon Society’s Blue List of species “which have recently given or are currently giving indications of non-cyclical population declines or range contractions either locally or widespread” (Tate 1981).