Female Survival Rates in a Declining White-Tailed Deer Population

Our objective was to identify seasonal and annual survival rates, in the context of habitat and other environmental conditions, necessary to identify ultimate causes of proximate mortality for white-tailed deer (Odocoileus virginianus) in the central Black Hills. From 1993 to 1996, we monitored radiocollared female (n=73) white-tailed deer in the central Black Hills of South Dakota and Wyoming. Natural mortality (i.e., from coyotes [Canus latrans], dogs, malnutrition, sickness, and unknown causes) (n=44, 71%) was the primary cause of female mortality, followed by harvest (n=14, 22.6%) and accidental causes (i.e., road kill and drowning) (n=4, 6.5%). More females died in spring (n=33, 53.2%) than in fall (n=14, 22.6%), winter (n=9, 14.5%), or summer (n=6, 9.7%). For the entire study period (1993-1996), survival rate for female white-tailed deer was 10.4%. Annual survival rates of females ranged from 50.3 to 62.1% and were similar among years (P=0.743). Intraseasonal survival rates for females differed between winter (P=0.003) and spring (P=0.014), whereas summer (P=0.073) and fall (P=0.404) were similar. High spring mortality of females was related to poor forage conditions on winter range and limited escape cover throughout the central Black Hills. We recommend the use of management techniques that promote overstory and understory plant diversity, such as aspen (Populus tremuloides) regeneration and prescribed burns, to improve the habitat in this region.