North American Crane Working Group


Date of this Version


Document Type



Lewis, James C., Roderick C. Drewien, Ernie Kuyt, and Jr. Charlie Sanchez. "Contaminants in Habitat, Tissues, and Eggs of Whooping Cranes.", In: Stahlecker D. W., ed. 1992. Proceedings of the Sixth North American Crane Workshop, Oct. 3-5, 1991, Regina, Sask. (Grand Island, NE.: North American Crane Working Group, 1992), 159-65.


Conference co-sponsored by the Canadian Wildlife Service, Saskatchewan Parks and Renewable Resources Department, and the Whooping Crane Conservation Association, Canadian Council. Proceedings used by permission of the North American Crane Working Group.


Sampling of contaminants in the principal habitat areas of whooping cranes (Grus americana) of both the Rocky Mountain and the Aransas/Wood Buffalo National Park whooping crane populations began in the mid-1980's. Contaminants in eggs and tissues of whooping cranes were sampled opportunistically since the 1960's. Chlorinated hydrocarbons existed in low levels in the environment. Some trace elements including aluminum, arsenic, cadmium, chromium, copper. mercury, selenium, and zinc are of sufficient abundance to justify continued monitoring. Declines over time in residues of DDT and mercury in tissues and eggs reflected the prohibition in use of these as pesticides or fungicides. Egg shell thickness did not differ significantly (P > 0.05) from pre-1910 levels. At present, we are unable to confirm any contaminant levels which threaten reproductive performance or bird survival. The major potential contaminant threats to whooping cranes continue to be accidental oil and hazardous substance spills along the Gulf Intracoastal Waterway of Texas.