9th International Deer Biology Congress

AUTHORS: John C. Kilgo, USDA Forest Service Southern Research Station

ABSTRACT: With a range covering much of North America, white-tailed deer (Odocoileus virginianus) encounter most large predator species on the continent. Wolves (Canis spp.), coyotes (Canis latrans), black bears (Ursus spp.), cougars (Felis concolor), and bobcats (Felis rufus) all can, in some situations, have important effects on deer population dynamics that must be considered in harvest management. After briefly reviewing general patterns in deer-predator relationships, I will focus particularly on how coyote range expansion has changed deer management in the southeastern US, using data from South Carolina (SC) as a case study. Coyotes colonized SC during the 1980s and their numbers increased through the early 2000s. The statewide deer population was itself increasing during this period, to the point of overabundance in some areas, in spite of a history of liberal harvest of both antlered and antlerless deer. However, the deer population plateaued during the late 1990s and by 2005 had decreased by 35%, coincident with increasing coyote numbers. At a low deer density study site in western SC, annual measures of recruitment had declined so research was initiated to investigate causes of fawn mortality. Fawn survival was only 23% and predation by coyotes accounted for 80% of all mortalities. Intensive coyote control conducted for three years yielded only marginal increases in annual fawn survival due to the quick recovery of the coyote population following trapping, with one of the three years realizing no increase at all. Although coyote control was not an effective tool to increase recruitment rate, total recruitment was increased by reducing antlerless harvest because predation on adult deer was not present or was insignificant. Thus, I suggest the statewide decline of deer during the early 2000s resulted from the combination of high levels of predation on fawns and liberal antlerless harvest. Reduced antlerless harvest since that time has stabilized the population trajectory. While not present in South Carolina prior to the 1980s, the advent of coyotes aided in slowing deer population growth but now requires more careful attention to sustainable harvest management in order to maintain healthy deer populations.