Survival of White-Tailed Deer Neonates in Minnesota and South Dakota

Understanding the influence of intrinsic (e. g., age, birth mass, and sex) and habitat factors on survival of neonate white-tailed deer improves understanding of population ecology. During 2002-2004, we captured and radiocollared 78 neonates in eastern South Dakota and southwestern Minnesota, of which 16 died before 1 September. Predation accounted for 80% of mortality; the remaining 20% was attributed to starvation. Canids (coyotes [Canis latrans], domestic dogs) accounted for 100% of predation on neonates. We used known fate analysis in Program MARK to estimate survival rates and investigate the influence of intrinsic and habitat variables on survival. We developed 2 a priori model sets, including intrinsic variables (model set 1) and habitat variables (model set 2; forested cover, wetlands, grasslands, and croplands). For model set 1, model {Sage-interval} had the lowest AIC(c) (Akaike's information criterion for small sample size) value, indicating that age at mortality (3-stage age-interval: 0-2 weeks, 2-8 weeks, and > 8 weeks) best explained survival. Model set 2 indicated that habitat variables did not further influence survival in the study area; beta-estimates and 95% confidence intervals for habitat variables in competing models encompassed zero; thus, we excluded these models from consideration. Overall survival rate using model {Sage-interval} was 0.87 (95% CI - 0.83-0.91); 61% of mortalities occurred at 0-2 weeks of age, 26% at 2-8 weeks of age, and 13% at > 8 weeks of age. Our results indicate that variables influencing survival may be area specific. Region-specific data are needed to determine influences of intrinsic and habitat variables on neonate survival before wildlife managers can determine which habitat management activities influence neonate populations. (C) 2011 The Wildlife Society.