Management of a central Illinois deer herd

Overabundant white-tailed deer herds often have negative impacts on forests such as impeding future regeneration of woody species, and extirpating spring wildflowers. Direct conflicts with humans also arise in the form of deer-vehicle collisions and agricultural depredation. Thus, reducing deer herds to sustainable levels has become a priority for resource managers. In this study I present the results of a white-tailed deer (Odocoileus virginianus) management program initiated in 2004 to reduce deer densities at Robert Allerton Park, historically a refuge from hunting, located in Monticello, IL. The project entailed monitoring deer densities by both visual and infrared helicopter surveys. The 600 hectare park had been closed to hunting until 2004 when a total of 730 deer were counted on the entire survey area (the park and the surrounding 2,953 ha). The deer management program (2004-2010) utilized archery and shotgun hunting combined with an initial 2 years of culling via sharp shooting. Hunters were required to volunteer 40 hours of service to the park, pass a target-proficiency test, comply with an earn-a-buck program (harvest a doe first), and follow all state hunting regulations. To monitor changes in deer densities, 15 aerial surveys were conducted over a two year period (2007-2009), including 7 visual flights over snow cover (Jan.-March) and 8 infrared flights. The helicopter survey results indicate that deer counts as indicated by infrared surveys and visual surveys over snow cover were similar (not significantly different). Infrared surveys extended the ability to count deer in the absence of snow cover. The hunting program has reduced deer densities, with a most recent visual aerial survey indicating 197 deer in 2010. The population is being maintained at current levels using archery hunting only. In the spring of 2009, evaluation of the status of spring wildflowers was considered for 207 selected upland sites in the park, replicating plant surveys conducted before management of the deer herd had begun. As would be expected, there is no clear indication of a recovery of spring wildflowers, given that deer numbers have only recently been reduced. The well documented Robert Allerton Park deer management effort builds on a wealth of deer research and monitoring of the population in the region over many decades. Hence, the study provides information that will be very useful in framing deer management programs elsewhere in the Midwest