Interannual Variability in Survival Rates for Adult Female White-Tailed Deer

Adult female survival is an important component to population models and management programs for white-tailed deer (Odocoileus virginianus), but short-term survival studies (1-3 yrs) may not accurately reflect the variation in interannual survival, which could alter management decisions. We monitored annual survival and cause-specific mortality rates of adult female white-tailed deer (n = 158) for 6 years (2010-2012, 2016-2018) in southern Delaware, USA. Annual survival rate differed among years. Survival rates (+/- SE) and mortality causes were similar in 3 years (2011 = 0.72 +/- 0.08, 2017 = 0.68 +/- 0.08, 2018 = 0.74 +/- 0.09) and comparable to previous research from mixed forest-agricultural landscapes. A relatively low survival rate in 2010 (0.48 +/- 0.11) was influenced by hunter harvest and potentially compounded by abnormally severe winter conditions in the prior year. A peracute outbreak of hemorrhagic disease occurred during summer 2012, resulting in an annual survival rate of 0.38 +/- 0.11, and to our knowledge is the first reported case of a hemorrhagic disease outbreak in a monitored wild population with known fates. In 2016, we did not observe any harvest mortality, resulting in high annual survival (0.96 +/- 0.04). Our results demonstrate the degree of variability in annual survival and cause-specific mortality rates within a population. We caution against the use of short-term survival studies to inform management decisions, particularly when incorporating survival data into population models or when setting harvest objectives. (c) 2020 The Wildlife Society.