North American Crane Working Group


Date of this Version


Document Type



Lewis, Thomas E., and R. Douglas Slack. "Whooping Crane Response to Disturbances at the Aransas National Wildlife Refuge.", 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), 176.


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.


Many forms of disturbance on and near the Aransas National Wildlife Refuge cause disruptions to wintering whooping cranes (Grus americana). Known forms of disturbance include various boating, aircraft, and automobile traffic. Natural disturbance from other wildlife also occurs. Behavioral observations and disturbance documentation have shown that Whooping cranes respond differently to various disturbances. Although airplane overflights, recreational boating, barge traffic. and workboat activity represent the most frequent disturbances to whooping cranes (22, 19, 14, and 13 %, respectively, of total disturbances), it appears that frequency of occurrence is less important than the disturbance class and distance from the cranes. Whooping cranes react most strongly to helicopters, airboats, tourboats, and other intruding whooping cranes when the activity is less than 1,000 m away, and flushing rates are 50, 38, 24, and 20%, respectively. Disturbance may severely impact maintenance of optimal energy budgets or cause injury to whooping cranes. These data represent preliminary results from the first year of a 2-year project.