Great Basin Naturalist


Five species of Ciconiiforms breed in Wyoming: the American Bittern (Botaurus lentiginosus), Great Blue Heron (Ardea herodias), Snowy Egret (Egretta thula), Black-crowned Night-Heron (Nycticorax nycticorax), and White-faced Ibis (Plegadis chihi). Field surveys conducted from 1984 through 1986 indicate that at least 151 Great Blue Heron colony sites exist in Wyoming, making it the most abundant and widespread Ciconiiform in the state. Only small breeding populations have been discovered for the remaining species. Except for the Snowy Egret, where numbers of active nests have remained relatively stable, population trends are unknown for the other species. We believe most colonies have been found in Wyoming, but additional inventories may result in the discovery of other nesting areas, especially for the Great Blue Heron.