Modeling deer herd management: sterilization is a viable option

Abstract

A closed-population demographic model was developed to examine population consequences of hunting, predation, and sterilization as methods of deer herd ( Odocoileus sp.) reduction strategies. Sterilization appears attractive where legislation or public pressure prevent hunting or other forms of culling. Sterilizing a fixed number of animals annually during the initial phase of a control program, and then reducing the number of annual sterilizations as herd size declines, will probably not be effective, as our model predicts only two outcomes: no reduction in herd size, or extinction. The number of annual sterilizations must be calculated based on the number of fertile females remaining in the herd, not on total herd size, and the number of annual sterilizations must be greatly reduced before total herd size decreases significantly. For Cumberland Island National Seashore, GA, the model predicts that the herd of 1500 deer can be controlled at 750. Over 3 years, an initial rate of 200 sterilizations per year is reduced to a constant rate of 42 per year. If the current levels of hunting and predation continue, the initial number of sterilizations is reduced from 200 to 81, but the constant annual rate increases to 58.