A long-term assessment of the effect of winter severity on the food habits of white-tailed deer

Abstract

Nutrition is a critical link between environmental and population variation in northern populations of free‐ranging white‐tailed deer (Odocoileus virginianus). Yet, few studies have investigated winter food habits of northern free‐ranging deer and all of these were short‐term studies (1–2 winters). Consequently, little information is available on the effect of inter‐annual variation in winter severity on browse availability and diet composition of free‐ranging deer. We describe winter browse use by white‐tailed deer on 4 study sites in northern Minnesota during 1991–2005. We also tested several a priori predictions about how browse use and availability would change as a function of winter severity. We collected browse data from 1,028 feeding trails and recorded 38 available browse species or species groups. The 4 most common browse species (beaked hazel [Corylus cornuta], mountain maple [Acer spicatum], trembling aspen [Populus tremuloides], and speckled alder [Alnus incana]) accounted for 76% of total available stems, and beaked hazel and mountain maple accounted for 68% of total used stems. As expected, browse use and availability distributions were very similar (i.e., deer used many of the available browse resources). Mean number of browse species used did not increase (decreased selection) with snow depth. However, mean browse rate (functional response) increased with increasing snow depth, and use of speckled alder (starvation food) increased when snow depth exceeded 40 cm. In addition, the number of browse species along feeding trails declined and stem abundance increased, on average, with increasing snow depth. Deep snow and increased use of dense conifer cover in northern Minnesota may restrict deer to greater use of lower quality feeding sites. In landscapes where this may occur, habitat management should attempt to minimize over‐browsing on feeding sites in proximity to dense conifer cover by maximizing browse abundance and availability, particularly for beaked hazel and mountain maple. Managers also should consider enhancing alternative early‐winter feeding sites. © 2013 The Wildlife Society. © The Wildlife Society, 2013

Influence of body mass and environmental conditions on winter mortality risk of a northern ungulate: Evidence for a late‐winter survival bottleneck

“…A decrease in deer mortality risk following snowmelt may be the result of several processes. First, deer foraging during deep snow conditions is mostly limited to food available along established trails, where preferred browse species become depleted throughout winter (DelGiudice, Sampson, & Giudice, 2013). Hobbs (1989) predicted that the energetic losses due to reduced forage intake and locomotion in deep snow were 5.4 times greater than losses due to increased thermoregulatory expenses in cold temperatures for mule deer (Odocoileous hemonius [Rafinesque 1817]).…”

Technological Advances Increase Fix‐Success for White‐Tailed Deer GPS Collars

“…Collars can be programmed to collect only QFP locations if location accuracy is not paramount to study objectives. The brief amount of time required to obtain a QFP‐fix can increase battery efficiency by 6–20% (Tomkiewicz et al 2010), which would prolong monitoring ability and be particularly advantageous to long‐term studies, as has been reported using VHF telemetry (DelGiudice et al 2013 a , b ). The ability to sample 100% of location‐fixes with high spatial accuracy will allow researchers to confidently monitor and assess terrestrial animals that consistently occupy cover types with dense canopy cover, with minimal data loss or habitat bias due to missed location‐fixes.…”

“…], and beaked hazel [ Corylus cornuta ]), and open field (0% canopy closure). The cover types are representative of those available and used by deer on the winter range study sites in northern Minnesota (DelGiudice et al 2013 a , b ; Smith 2020). We used a spherical convex densitometer (Model A 43887; Forestry Suppliers, Jackson, MS, USA) to confirm percent canopy closure for the dense conifer cover type.…”

Understanding environmental patterns of canid predation on white-tailed deer (Odocoileus virginianus)

“…We hypothesized that mortality risk would decrease with increasing human development (Hebblewhite et al 2005b;Wang et al 2015), agriculture (Muhly et al 2011), and coniferous cover (Ozoga 1968;Nelson and Mech 1981;Delgiudice et al 2013). Because population dynamics may vary at small spatial scales, understanding the relative impact of environmental D r a f t factors on the outcome of white-tailed deer encounters with canids may be important for justifying landscape and wildlife management.…”

“…Cover CONF During the winter, coniferous cover provides thermal benefits and increased ability to avoid predators (Delgiudice et al 2013;Nelson and Mech 1981;Ozoga 1968).…”