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On large management units where terrain allows observation of white‐tailed deer (Odocoileus virginianus) from the air, helicopter surveys may provide managers with cost‐effective and accurate estimates of population abundance; however, imperfect detection of deer introduces negative bias. This can result in potentially inappropriate management recommendations (e.g., harvest prescriptions). Sightability estimators are designed to model detection heterogeneity based on factors that affect observer detection of target animals. Sightability models are widely used to estimate ungulate abundance; however, previous researchers have developed sightability models using radio‐collared animals, potentially introducing bias during model development attributed to unaccounted for movement between initial and follow‐up flights. Therefore, our objectives were to model detection probability using surrogates of white‐tailed deer as a function of covariates including distance from transect, vegetative obstruction, and light conditions to improve population estimates derived from helicopter surveys and apply our final sightability model in operational helicopter surveys. We conducted our study in 2019 on a 399.4‐km2study area within a 1,210‐km2cattle ranch in central Florida, USA. We placed 3‐dimensional archery targets as surrogates for white‐tailed deer at assigned locations unknown to observers across a combination of stratified bins of vegetative obstruction and distances from the transect. Our top model indicated that distance from the transect and vegetative obstruction negatively affected detection of deer. Detection probability on the flight transect ranged from 0.95 (95% CI = 0.89–0.98) for vegetative obstruction 0–25% and distance from transect 0–25 m to 0.05 (95% CI = 0.01–0.18) for vegetative obstruction 76–100% and distance from transect 100–125 m. We applied our sightability model to operational surveys on 3 units, which produced population estimates averaging 26% higher than those derived from uncorrected counts. Observers simultaneously recorded live deer during operational flights, of which 60% of deer groups were observed while stationary. Our methods using stationary surrogates to develop region‐specific sightability models could be used in other study areas to account for imperfect detection of white‐tailed deer. © 2021 The Wildlife Society. Vegetation obstruction and distance from transect negatively influenced detection probability of white‐tailed deer during helicopter surveys. Using surrogates for sightability model development minimized bias because locations of inanimate objects are known with absolute certainty, which may not be the case even for high‐resolution global positioning system location data associated with marked animals.

Understanding space‐use patterns by elk (Cervus canadensis) is essential to alleviating human‐elk conflicts, particularly when crop depredation by elk can make it harder to justify to the public the need to restore elk populations to regions with agricultural landscapes. In 2016–2017, we used global positioning system data from 20 female elk to investigate their selection for agricultural cover during the agricultural season (1 May–31 Oct) in northwestern Minnesota, USA. We estimated resource selection functions with resource availability defined at the home range scale. Elk space use was primarily determined by distance to forest cover in areas proximate to agricultural fields. During diurnal periods, elk selected areas with forest cover near agricultural fields planted with legumes and cereal. During nocturnal periods, elk selected for agricultural fields with little to no canopy and that were planted with legumes. We suggest that management of elk in northwestern Minnesota will require practices that discourage the use of agriculture by elk while improving natural habitats within areas managed for elk restoration. We suggest that forestry practices (i.e., thinning and burning) could improve cover and forage openings for elk in restoration areas. Furthermore, managers could work with agricultural producers where elk occur to plant crops favored by elk (i.e., legumes) outside known home ranges and plant fields within home ranges with crops that elk avoided (i.e., hay). Collectively, these practices may shift the ranges of elk herds into restoration areas and lower conflict between the public and elk restoration efforts. © 2020 The Wildlife Society. Female elk in our study responded positively to edge density and interspersion of natural and agricultural land cover, suggesting that cover heterogeneity is important for providing sufficient cover and food resources to elk throughout the year. Management of elk in northwestern Minnesota will require management practices that discourage the use of agricultural areas by elk that create conflict between the public and elk restoration efforts while improving elk habitat in other areas to meet the foraging needs of female elk and their calves so that most of their life requisites are achieved on restoration areas rather than adjacent agricultural lands.

ABSTRACT We evaluated efficacy of sound as a deterrent for reducing deer (Odocoileusspp.)–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.

Abstract:Basic knowledge of white‐tailed deer (Odocoileus virginianus) hearing can improve understanding of deer behavior and may assist in the development of effective deterrent strategies. Using auditory brainstem response testing, we determined that white‐tailed deer hear within the range of frequencies we tested, between 0.25–30 kilohertz (kHz), with best sensitivity between 4–8 kHz. The upper limit of human hearing lies at about 20 kHz, whereas we demonstrated that white‐tailed deer detected frequencies to at least 30 kHz. This difference suggests that research on the use of ultrasonic (frequencies >20 kHz) auditory deterrents is justified as a possible means of reducing deer—human conflicts.

Abstract: Social behavior of white-tailed deer (Odocoileus virginianus) can have important management implications. The formation of matrilineal social groups among female deer has been documented and management strategies have been proposed based on this well-developed social structure. Using radiocollared (n= 17) and hunter or vehicle-killed (n= 21) does, we examined spatial and genetic structure in white-tailed deer on a 7,000-ha portion of the Savannah River Site in the upper Coastal Plain of South Carolina, USA. We used 14 microsatellite DNA loci to calculate pairwise relatedness among individual deer and to assign doe pairs to putative relationship categories. Linear distance and genetic relatedness were weakly correlated (r= -0.08, P= 0.058). Relationship categories differed in mean spatial distance, but only 60% of first-degree-related doe pairs (full sibling or mother-offspring pairs) and 38% of second-degree-related doe pairs (half sibling, grandmother-granddaughter pairs) were members of the same social group based on spatial association. Heavy hunting pressure in this population has created a young age structure among does, where the average age is <2.5 years, and <4% of does are >4.5 years old. This—combined with potentially elevated dispersal among young does—could limit the formation of persistent, cohesive social groups. Our results question the universal applicability of recently proposed models of spatial and genetic structuring in white-tailed deer, particularly in areas with differing harvest histories.