A biologist at Washington University in St. Louis and Missouri state conservationists have devised a new method to census deer populations in wooded urban areas. The method could serve as a model for similar urban/suburban regions nationwide facing the increasing nuisance and ecological nightmare of civilization colliding with nature.
Owen J. Sexton, Ph.D., Washington University professor emeritus of biology in Arts and Sciences, and Missouri Department of Conservation biologists Jeff Beringer and Lonnie P. Hansen employed air power, high technology and Mother Nature to count the number of deer at Washington University's Tyson Research Center, a 2,000-acre oak- and hickory-dominated ecological site on the outskirts of metropolitan St. Louis. Sexton is the director of Tyson Research Center. Their method relies on helicopter sightings from trained observers over a topography covered by about six inches of snow. The snow is helpful as a visual aid to distinguish deer from forest undergrowth. While helicopters flying over snow-covered terrain have been combined in other studies, no other scientists have employed a Global Positioning System (GPS), a sophisticated, geographical tool linked to a satellite that gives accurate geographical coordinates, minimizing the chance of the helicopter and observers straying off their designated flight paths. Departure from a flight path increases the chance of counting the same deer more than once.
The study also is the first over a wooded, urban terrain to report such a high detection rate of deer -- 79 percent. The detection rate is a numerical indication of the likelihood that all deer in the area were counted. Sexton, Beringer and Hansen published their study in the spring issue of Wildlife Society Bulletin, Volume 26, 1998.
The census results were a surprise and will help Sexton and others develop a
rational plan to keep the deer herd compatible with Tyson Research Center goals
Contact: Tony Fitzpatrick
Washington University in St. Louis