Landscape Features Fail to Explain Spatial Genetic Structure in White-Tailed Deer Across Ohio,USA

Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches are increasingly used to better understand potential pathways for CWD spread in white-tailed deer, but little is known about genetic structure of white-tailed deer in Ohio. The objectives of our study were to evaluate spatial genetic structure in white-tailed deer across Ohio and compare the support for isolation by distance (IBD) and isolation by landscape resistance (IBR) models in explaining this structure. We collected genetic data from 619 individual deer from 24 counties across Ohio during 2007–2009. We used microsatellite genotypes from 619 individuals genotyped at 11 loci and haplotypes from a 547-base pair fragment of the mitochondrial DNA control region. We used spatial and non-spatial genetic clustering tests to evaluate genetic structure in both types of genetic data and empirically optimized landscape resistance surfaces to compare IBD and IBR using microsatellite data. Non-spatial genetic clustering tests failed to detect spatial genetic structure, whereas spatial genetic clustering tests indicated subtle spatial genetic structure. The IBD model consistently outperformed IBR models that included land cover, traffic volume, and streams. Our results indicated widespread genetic connectivity of white-tailed deer across Ohio and negligible effects of landscape features. These patterns likely reflect some combination of minimal resistive effects of landscape features on white-tail deer movement in Ohio and the effects of regional recolonization or translocation. We encourage continued CWD surveillance in Ohio, particularly in the proximity of confirmed cases. © 2021 The Wildlife Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.     

Effects of Impact Perception on Acceptance Capacity for White-Tailed Deer

ABSTRACT Wildlife professionals require conceptually sound methods to integrate biological and social insights for management of wildlife. The concept of acceptance capacity has been suggested to stimulate integration, although methods to link measures of acceptance capacity with measures of wildlife populations are not fully developed. To clarify relationships between acceptance capacity, wildlife populations, and human values, we explored effects of stakeholder characteristics and impact perception (the recognized, important effects arising from interactions with wildlife) on acceptance capacity. We used a mail-back questionnaire (n = 2,190 responses) to rural residents of southern Michigan 1) to examine whether 3 commonly identified stakeholder groups (hunters, farmers, and nonhunting, nonfarming rural residents) that share a common landscape also perceive similar suites of impacts and hold comparable acceptance capacities for white-tailed deer, and 2) to develop an explanatory model of acceptance capacity for deer. Comparisons among stakeholder groups revealed differences in perception of impacts resulting from interactions with deer; however, participation in hunting and farming were poor predictors of acceptance capacity for deer. Model selection criteria indicate that total effect of impacts perceived explains a majority of variation in acceptance capacity. We conclude that impact perception is a meaningful concept for integration of human values into management of wildlife populations because impacts relate to effects of current wildlife populations and can lead to management actions that address needs and interests of multiple stakeholder groups in changing landscapes.     

White-Tailed Deer Antler Research: A Response to Demarais and Strickland

ABSTRACT Demarais and Strickland presented several questions about the scope and validity of conclusions regarding predictability of mature antler size based on yearling antler size and produced a simulation model reported to demonstrate measurement bias in our 2008 study. We believe our conclusions were appropriate with our research hypothesis and demonstrated the assumed differential selection bias by hunters used in Demarais and Strickland was unwarranted. Demarais and Strickland provided no metadata to document the provenance of data used in their model and did not account for location, year, cohort, nutrition of research animals, or loss of individuals from their sample population by accidents or death: the same questions raised in their critique. Additionally, selection and experimental design problems in a portion of their sample population indicate their model results are questionable. Our responses to Demarais and Strickland will aid wildlife managers in making future culling decisions in white-tailed deer management.     

Influence of Landscape Composition and Structure on Antler Size of White-Tailed Deer

Abstract: Cause for spatial variation in phenotypic quality of white-tailed deer (Odocoileus virginianus) populations is of great interest to wildlife managers. Relating phenotypic variation of populations to large-scale land-use patterns may provide insight into why populations exhibit spatial variation and elucidate how management can influence population phenotype. We used an information-theoretic approach to relate average antler size of 203 deer populations to composition and structure of the habitat occupied by those populations. We used interspersion, edge, and diversity indices to represent habitat structure and percentage of area in vegetation types to represent habitat composition. Landscape composition was a better predictor of deer population antler size than was landscape structure. Percentages of the management unit in agriculture, pasture, and pine forest were variables commonly found in the region-specific set of best models. Model-averaged estimates of agriculture and pasture parameters were always positive and estimates of pine forest parameters were always negative, which suggests that land-use types that promote growth of early successional herbaceous plants will positively influence antler size and, most likely, body growth and reproduction of white-tailed deer populations. Conversely, our findings suggest landscapes dominated by pine forests did not provide optimal amounts of quality forages for white-tailed deer. Pine forest effects should be mitigated using a combination of increased harvest to lower deer density and silvicultural practices like thinning, prescribed burning, and selective herbicide applications that stimulate growth of high-quality forages beneath the forest canopy to improve deer phenotypic quality.     

Survival and Cause-Specific Mortality of Mature Male White-Tailed Deer

ABSTRACT Understanding sources of male deer mortality is a prerequisite to a successful management program, especially in Texas, USA, where white-tailed deer (Odocoileus virginianus) are the most economically important game species. South Texas, USA, is one of the few areas where males reach older age classes (> 4.5 yr), in part because of intense population management. Therefore, we obtained survival rates and causes of mortality of 48 mature male deer in south Texas, USA, over 2 years. We calculated Kaplan—Meier survival estimates during 2 study years modified for a staggered-entry design and annual survival rates for one cohort of deer from 1998 to 2004 using recapture and radiotelemetry data. We documented 21 mortalities (16 harvest and 5 nonhunting mortalities). Average annual survival of the known-aged 1998 cohort was 82% with 52% of surviving to 6.5 years of age. Survival in study year 2 (0.497 ± 0.069) was less than in study year 1 (0.781 ± 0.073; P = 0.0047), largely because males had finally reached harvestable age (> 6.5 yr old). All but one non-harvest mortality occurred during the rut or postrut periods. It appears that a large percentage of males can reach mature age classes under intense population management, making them available for harvest when at peak antler size. This allows for increased economic returns on intensively managed white-tailed deer populations.     

Home Range and Movement Rates of Female Exurban White-Tailed Deer

ABSTRACT White-tailed deer (Odocoileus virginianus) thrive in fragmented exurban habitats, resulting in increased occurrences of deer-human conflicts. To develop successful management regimes managers must understand exurban deer ecology, an area deficient in current literature. We investigated exurban white-tailed deer spatial ecology on Fair Hill Natural Resource Management Area in Cecil County, Maryland, USA. From June 2004 to January 2006, we collected 37,384 telemetry locations and 1,194 visual observations on 66 radiocollared female white-tailed deer to investigate seasonal home range sizes, home range fidelity, and hourly movement rates. Annual adaptive-kernel home range size ranged from 8.1 ha to 21.7 ha and 70.9 ha to 144.5 ha among seasons (early, middle, and late-hunting, posthunting, and fawning) at the 50% and 95% utilization distributions, respectively. Seasonal home range size generally increased from the fawning through posthunting seasons. Seasonal home range overlap differed at 50% and 95% utilization distributions, with the least overlap occurring between the posthunting and fawning seasons (50%: x̄ = 19.4%, 95%: x̄ = 33.3%). Circadian activity varied among seasons with dusk movement rates greatest in all seasons. Our results suggest that this exurban white-tailed deer population resided on similar ranges throughout the year, making individuals available for harvest during traditional harvest seasons. To maximize deer—hunter contact, efforts should be focused around the dusk activity period to coincide with peak deer activity.     

White-Tailed Deer Antler Research: A Critique of Design and Analysis Methodology

ABSTRACT Debate within the popular and technical literature regarding predictability of antler size at maturity based on 1.5-year antler size in white-tailed deer (Odocoileus virginianus) has led to confusion and uncertainty within constituent groups. Koerth and Kroll (2008) provided measures of age-related antler development using recaptures of known-age males from 12 deer populations in southern Texas. Several design and analysis issues reduce the scope and validity of their conclusion that amount of growth in the first set of antlers was a poor predictor of antler growth at maturity. Although unstated, the statistical hypothesis they tested did not coincide with their specific conclusions. Using a simulation, we show that their methods were susceptible to measurement bias. Their results are applicable only to populations with similar culling and management programs. Additionally, we provide recommendations for future research projects that evaluate predictability of antler size at maturity based on antler size at younger ages.     

Reduction and Maintenance of a White-Tailed Deer Herd in Central Massachusetts

Abstract: Controlled public hunts have been used in a variety of settings to reduce overabundant white-tailed deer (Odocoileus virginianus) herds. We present the results of a large-scale (160 km²) controlled hunt at Quabbin Reservation (QR) in central Massachusetts, USA. The QR was divided into 5 hunt zones. Hunting was initiated in each zone from 1991 to 1994 and continued through 2004. The management goal was to achieve posthunt deer densities of4 deer/km². Initial estimated deer densities in each zone ranged from 11.4 deer/km² to 27.6 deer/km². The management goals were reached in each zone after 2-4 years of hunting. Posthunt populations were maintained at or below the goal even though total hunter effort was reduced. Hunters were not required to harvest antlerless deer, but antlerless deer comprised 55-83% of the harvest each year. We simulated the effects of 5 years without hunting on deer populations. The simulated deer population exceeded management goals after 2 years. Our results demonstrate that controlled public deer hunts can effectively reduce deer populations and maintain them at desired levels over large areas with minimal hunter restrictions. Managers should prepare stakeholders during the hunt planning process for the need to continue overall harvest rates of >30% during the maintenance phase of a deer management program.     

Evaluating the effect of predators on white-tailed deer: Movement and diet of coyotes

Coyotes (Canis latrans) may affect adult and neonate white-tailed deer (Odocoileus virginianus) survival and have been implicated as a contributor to the decline of deer populations. Additionally, coyote diet composition is influenced by prey availability, season, and region. Because coyote movement and diet vary by region, local data are important to understand coyote population dynamics and their impact on prey species. In southeast Minnesota, we investigated the effect of coyotes on white-tailed deer populations by documenting movement rates, distances moved, and habitats searched by coyotes during fawning and nonfawning periods. Additionally, we determined survival, cause-specific mortality, and seasonal diet composition of coyotes. From 2001 to 2003, we captured and radiocollared 30 coyotes. Per-hour rate of movement averaged 0.87 km and was greater (P = 0.046) during the fawning (1.07 km) than the nonfawning period (0.80 km); areas searched were similar (P = 0.175) between seasons. Coyote habitat use differed during both seasons; habitats were not used in proportion to their availability (P < 0.001). Croplands were used more (P < 0.001) than their proportional availability during both seasons. Use of grasslands was greater during the fawning period (P = 0.030), whereas use of cropland was greater in the nonfawning period (P < 0.001). We collected 66 fecal samples during the nonfawning period; coyote diets were primarily composed of Microtus spp. (65.2%), and consumption of deer was 9.1%. During the study, 19 coyotes died; annual survival rate range was 0.33–0.41, which was low compared with other studies. Consumption of deer was low and coyotes searched open areas (i.e., cropland) more than fawning areas with dense cover. These factors in addition to high coyote mortality suggested that coyote predation was not likely limiting white-tailed deer populations in southeast Minnesota. © 2011 The Wildlife Society.     

Enhancing the Perceived Threat of Vehicle Approach to Deer

ABSTRACT In North America and Europe, deer (Cervidae)—vehicle collisions (DVCs) are common and result not only in injury and death to the animals involved, but also human injury and property damage. Given that most DVCs occur during crepuscular periods, we questioned whether the perceived threat to deer posed by vehicle approach could be enhanced. We hypothesized that a vehicle-based lighting system that better complements peak visual capabilities of deer at night relative to standard tungsten-halogen (TH) lighting alone would elicit a greater flight-initiation distance (FID) by free-ranging white-tailed deer (Odocoileus virginianus). Our lighting system comprised 2 TH lamps and one Xenarc high-intensity discharge (HID) lamp. We defined an a priori logistic model comprising 4 variables potentially explaining deer FID relative to vehicle approach: 1) starting distance of the approach, 2) lighting treatment, 3) season, and 4) deer group size. Deer exposed to the combination of TH lamps and constant illumination of the HID lamp exhibited a mean (SD) FID of 136 (127) m. In contrast, deer exposed to TH lamps only initiated flight on average at 116 (127) m, and those exposed to the combination of TH lamps and the HID lamp pulsed at 2 Hz exhibited a mean FID of 89 (98) m. We contend that the pulsing of the HID lamp while TH lamps were illuminated resulted in consistent loss (over approx. 0.5-sec intervals) of a portion of the image on approach, possibly interfering with sensory information relative to the position of the potential threat. In contrast, the combination of TH lamps and constant illumination of the HID lamp contributed (P = 0.033) to the probability of a FID ≥94 m. We suggest, therefore, that deer FID can be increased by combining currently available TH and HID lamps, or use of HID lamps alone, to enhance detection of an approaching vehicle at night. Also, we encourage research into new lamp designs to better complement deer visual capabilities as well as continued research to quantify deer FID in response to vehicle approach at night and lamp-specific properties that can enhance deer detection of the vehicle.     

Deer Responses to Sounds From a Vehicle-Mounted Sound-Production System

ABSTRACT We evaluated efficacy of sound as a deterrent for reducing deer (Odocoileus spp.)–vehicle collisions by observing behavioral responses of free-ranging white-tailed deer (O. virginianus) to pure-tone sounds within their documented range of hearing. Behavior of free-ranging deer within 10 m of roadways was not altered in response to a moving automobile fitted with a sound-producing device and speakers that produced 5 sound treatments documented to be within the hearing range of white-tailed deer. Many commercially available, vehicle-mounted auditory deterrents (i.e., deer whistles) are purported to emit continuous pure-tone sounds similar to those we tested. However, our data suggest that deer whistles are likely not effective in altering deer behavior in a manner that would prevent deer-vehicle collisions.     

Assessment of Abilities of White-Tailed Deer to Jump Fences

Abstract: There is a need for insight into fence heights required for impeding white-tailed deer (Odocoileus virginianus). We evaluated the ability of wild-caught deer to jump progressively taller fences and documented deterrence rates of 0% for fences ≤1.5 m followed by increasing deterrence rates of 14% at 1.8 m, 85% at 2.1 m, and 100% at 2.4 m. We documented 100% deterrence rates during 5 additional experiments with different deer and the test fence at 2.4 m, a common height of fences at captive deer facilities. Our results will be valuable to those managing spread of wildlife diseases, deer-vehicle collisions, and agricultural damage.     

Evaluating Differences in Harvest Data Used in the Sex-Age-Kill Deer Population Model

Abstract: A steady increase in archery hunting participation and frequent changes in hunter regulations led to an evaluation of harvest data used in a common white-tailed deer (Odocoileus virginianus) population model. Our goal was to determine if model parameters and population estimates traditionally estimated solely by firearm harvest data were biased with respect to altered sex and age ratios brought about by increases in archery hunting and harvest success. The sex-age-kill (SAK) model, commonly used by state agencies, was developed in the mid-1900s when deer numbers were low and firearm harvest was predominant. Management actions were concentrated on increasing deer numbers, and model assumptions relied heavily on a stable age distribution and a minimal antlerless deer harvest. We evaluated the reliance of SAK in a modern hunting scenario using a 10-year dataset obtained from Michigan, USA, that encompassed a variety of climatic regions, hunting seasons, and regulation scenarios. We found that firearm and archery harvest sex and age ratios differed among 5 geographic groups and study years for males, females, and fawns (P<0.001, P = 0.001, and P = 0.037, respectively). Also, the addition of archery harvest data increased population estimates but did not alter overall trends. We recommend that managers reassess harvest-based population estimates in 2 situations: 1) if regulation changes affect antlerless deer harvest, and 2) when trends in hunter success rates cause fluctuations in harvest data.     

Response of Deer to Containment by a Poly-Mesh Fence for Mitigating Disease Outbreaks

Abstract: Rapidly deployable and effective methods are needed to contain free-ranging deer (Odocoileus spp.) during acute disease outbreaks. We evaluated efficacy of a 2.1-m-tall polypropylene mesh (poly-mesh) fence for containing ≥15 free-ranging white-tailed deer (O. virginianus) within a 42-ha area in eastern Nebraska, USA. We observed a 99% decrease in deer leaving the enclosure area after we installed fencing (1 deer jumped; 0.02 deer/hr) compared with prefence rates (5.26 deer/hr). However, 8 deer (53% of censused population) escaped the enclosure during a census drive after our study. Poly-mesh fencing may be effective in temporarily containing free-ranging deer during minimally disruptive deer removal actions such as trapping or sharpshooting.     

Space Use and Survival of White-Tailed Deer in an Exurban Landscape

Abstract: Exurban development is nonmetropolitan, residential development characterized by a human population density and average property size intermediate between suburban and rural areas. Although growth in exurban areas is outpacing that of urban, suburban, or rural landscapes, studies of deer (Odocoileus spp.) ecology in exurban areas are nonexistent. During 2003–2005, we studied space use (i.e., seasonal home-range and core-area size and habitat use relative to human dwellings) and survival of 43 female white-tailed deer (O. virginianus) in an exurban setting near Carbondale, Illinois. Deer had larger home ranges than most suburban deer populations and generally smaller home ranges than rural deer populations. When we analytically controlled for habitat use, deer exhibited a subtle avoidance of human dwellings, especially during the fawning season. The annual survival rate was among the highest reported in the literature at 0.872 (SE = 0.048). Only 5 deer (cause-specific mortality rate = 0.091) were harvested by hunters, indicating major obstacles for wildlife managers when attempting to manage deer in exurban areas using traditional hunter harvest.     

Effects of Maternal Status on the Movement and Mortality of Sterilized Female White-Tailed Deer

Abstract: Surgical sterilization by tubal ligation has been proposed as a technique for controlling white-tailed deer (Odocoileus virginianus) populations in urban or suburban areas where other forms of population control are impractical, but little is known about demographic rates in populations under management with surgical sterilization. We analyzed seasonal movement and mortality data collected during a 4-year study of surgical sterilization in suburban Chicago, Illinois, USA. We calculated 323 home range size estimates for 62 individual females within season and year. Non-gravid females without young exhibited home range sizes 52% larger than gravid females and females with fawns. Mortality rate was positively correlated with home range size. We suggest that the increased mortality rate observed in surgically sterilized females may be due to greater movement by non-maternal females. Population managers will need to account for potential effects of maternal status on movement and mortality when considering the use of sterilization for management of suburban populations of white-tailed deer.     

Survival of White-Tailed Deer Fawns in Southern Illinois

Abstract: Survival of white-tailed deer (Odocoileus virginianus) fawns has been quantified throughout much of North America. However, few studies have assessed the influence of intrinsic factors (e.g., fawn age and birth mass) and habitat on fawn survival. During 2002-2004, we captured and radiocollared 166 fawns in southern Illinois, USA, to estimate survival rates, determine causes of mortality, and identify factors influencing fawn survival. We used a known fates model in program MARK to estimate survival rates and compare explanatory models based on Akaike's Information Criterion corrected for small sample sizes (AIC_c). We developed 2 candidate sets of a priori models to quantify factors influencing fawn survival: model set 1 included intrinsic factors and model set 2 focused on habitat variables. We recorded 64 mortalities and the overall survival rate was 0.59 (95% CI = 0.51-0.68). Predation was the leading source of mortality (64%) and coyotes (Canis latrans) were the most prominent predator. For model set 1, model {S_{age X year}} had the lowest AIC_c value suggesting that the age at mortality varied among capture years. For model set 2, model {S_{landscape+forest}} had the lowest AIC_c value and indicated that areas inhabited by surviving fawns were characterized by a few large (i.e., > 5 ha) irregular forest patches adjacent to several small nonforest patches, and survival areas also contained more edge habitat than mortality areas. Due to the magnitude of coyote predation, survival areas could have represented landscapes where coyotes were less effective at locating and capturing fawns when compared to mortality areas. This study was the first account of macrohabitat characteristics directly influencing fawn survival. Wildlife managers can use this information to determine how habitat management activities may affect deer populations.     

Cougar Prey Selection in a White-Tailed Deer and Mule Deer Community

Abstract Widespread mule deer (Odocoilus hemionous) declines coupled with white-tailed deer (O. virginianus) increases prompted us to investigate the role of cougar (Puma concolor) predation in a white-tailed deer, mule deer, and cougar community in northeast Washington, USA. We hypothesized that cougars select for and disproportionately prey on mule deer in such multiple-prey communities. We estimated relative annual and seasonal prey abundance (prey availability) and documented 60 cougar kills (prey usage) from 2002 to 2004. White-tailed deer and mule deer comprised 72% and 28% of the total large prey population and 60% and 40% of the total large prey killed, respectively. Cougars selected for mule deer on an annual basis (α_md = 0.63 vs. α_wt = 0.37; P = 0.066). We also detected strong seasonal selection for mule deer with cougars killing more mule deer in summer (α_md = 0.64) but not in winter (α_md = 0.53). Cougars showed no seasonal selection for white-tailed deer despite their higher relative abundance. The mean annual kill interval of 6.68 days between kills varied little by season (winter = 7.0 days/kill, summer = 6.6 days/kill; P = 0.78) or prey species (white-tailed deer = 7.0 days/kill, mule deer = 6.1 days/kill; P = 0.58). Kill locations for both prey species occurred at higher elevations during summer months (summer = 1,090 m, winter = 908 m; P = 0.066). We suspect that cougars are primarily subsisting on abundant white-tailed deer during winter but following these deer to higher elevations as they migrate to their summer ranges, resulting in a greater spatial overlap between cougars and mule deer and disproportionate predation on mule deer.     

Evaluating the Mechanisms of Landscape Change on White-Tailed Deer Populations

Understanding how landscape change influences the distribution and densities of species, and the consequences of these changes, is a central question in modern ecology. The distribution of white-tailed deer (Odocoileus virginianus) is expanding across North America, and in some areas, this pattern has led to an increase in predators and consequently higher predation rates on woodland caribou (Rangifer tarandus caribou)—an alternate prey species that is declining across western Canada. Understanding the factors influencing deer distribution has therefore become important for effective conservation of caribou in Canada. Changing climate and anthropogenic landscape alteration are hypothesized to facilitate white-tailed deer expansion. Yet, climate and habitat alteration are spatiotemporally correlated, making these factors difficult to isolate. Our study evaluates the relative effects of snow conditions and human-modified habitat (habitat alteration) across space on white-tailed deer presence and relative density. We modeled deer response to snow depth and anthropogenic habitat alteration across a large latitudinal gradient (49° to 60°) in Alberta, Canada, using motion-sensitive camera data collected in winter and spring from 2015 to 2019. Deer distribution in winter and spring were best explained by models including both snow depth and habitat alteration. Sites with shallower snow had higher deer presence regardless of latitude. Increased habitat alteration increased deer presence in the northern portion of the study area only. Winter deer density was best explained by snow depth only, whereas spring density was best explained by both habitat alteration and the previous winter's snow depth. Our results suggest that limiting future habitat alteration or restoring habitat can alter deer distribution, thereby potentially slowing or reversing expansion, but that climate plays a significant role beyond what managers can influence. © 2020 The Wildlife Society.