Effects of supplemental feeding and deer density on white-tailed deer diet selection and antler growth

Provision of supplemental feed to increase survival and productivity of white-tailed deer (Odocoileus virginianus) is an increasingly common management practice. I conducted 2 studies evaluating effects of supplemental feed on diet selection and effects of supplemental feed and deer density on antler growth. I evaluated effects of supplemental feed on diet composition of tame female deer released into 4 81-ha enclosures. Two had a pelleted supplement provided ad libitum and 2 had no supplement. I compared antler size of deer living in 12 81-ha enclosures in a factorial arrangement of 3 deer densities with presence or absence of supplemental feed. I collected bite-count data seasonally from April 2007 through February 2009 to estimate proportion of shrubs, sub-shrubs, forbs, grass, mast, cacti, flowers, dead leaves, and fungi in deer diets. Diets of supplemented deer contained 1.3 times more ( P=0.068) shrubs than unsupplemented deer. Unsupplemented deer diets contained 4 times (P=0.040) more sub-shrubs than supplemented deer during summer and 4.5 times more (P=0.009) during autumn. Diets of unsupplemented deer contained 2.4 times more (P=0.006) mast than supplemented deer during spring 2008 and 16 times more ( P=0.062) during autumn 2008. During winter 2007, unsupplemented deer diets contained 3.6 times more (P<0.001) flowers than supplemented deer. During winter, supplemented deer consumed 12.4 times more (P<0.001) dead leaves than unsupplemented. Supplemented yearling males (41%; 18 of 44) were less (P=0.067) likely to be spikes (≤2 antler points) than unsupplemented males (95%; 19 of 20). Deer density did not affect probability of spike-antlered yearlings occurring (P=0.486). The effects of deer density on gross B&C score depended (P=0.004) on supplemental treatment. Gross B&C score decreased (P=0.008) 1.3 cm for each additional deer in unsupplemented enclosures. Gross B&C score of supplemented mature males was not affected (P=0.121) by density.