A spatially explicit model of the white- tailed deer population in Delaware

Population models of white-tailed deer (Odocoileus virginianus) are used by many states to predict population levels and aid in making management decisions. Delaware did not have a deer population model, so we developed one and used it to investigate the implications of changes to the harvest. We modeled 7 changes to the harvest regime and compared these changes to the base line of no changes to the harvest regime. We used survival rates, reproductive rates, harvest data, a population estimate, and spotlight counts to construct the model. The model scenario began in February 2006 and ran until August 2014. Without changing the harvest regime, our model predicted the state deer population to decrease 28%. Allowing Sunday hunting during the opening weekend of the main firearm season and adding an additional week to the main firearm season caused the population to decline at a greater rate. Terminating the Severe Deer Damage Program did not impact the predicted population. Closing the October season for hunting antlerless deer and the January shotgun season both caused a 23% increase to the predicted deer population. The deer population was 11% greater with the January closing of the muzzleloader season and 37% greater with both January shotgun and muzzleloader seasons closed. The model showed that the 17 deer management zones in Delaware have very different population levels and harvest rates. To date, the harvest regimes in Delaware have been changed only at the state level, but future changes to harvest regimes should occur at the zone level.