2025 Southeast Deer Study Group

Welcome - Jonathan Trudeau
SEDSG Chair Address - Dr. Gino D’Angelo
Welcome to DE and MD - Pat Emory & Brian Eyler

Regional efforts to understand the causes of disease in white-tailed deer and the impact of those diseases on populations have a long history in the Southeast. The deer health/disease challenges faced by state wildlife management agencies over the last 50+ years have varied. Once upon a time, a primary challenge was the lack of a basic understanding of deer health and disease in recovering populations. Today, managers often face challenging aspects of deer diseases that go beyond biology and are instead rooted in a variety of social, political, and economic factors. Appropriately interpreting and communicating complex disease topics is of increasing importance. Further, strong partnerships and interdisciplinary collaborations are critical as deer managers navigate the abundance of differing perspectives, opinions, and motivations related to deer health and disease.

Historically, deer managers had a full plate with responsibilities related to hunting, seasons, and stakeholders. In recent decades, looming disease issues have stretched responsibilities further. How can “we” tackle these challenges together? Solutions may include minimizing risks, data coordination, decision-support tools, and communication strategies, but require a forward-looking perspective on time investment and agency administration priorities.

Animal movement is shaped by the environment and the necessity to engage in essential activities. Animals must use urban and rural environments in different ways to meet food, cover, and reproduction needs. Urban deer present management challenges, and understanding deer movement with respect to developing landscapes is critical to inform effective deer management decisions that promote sustainable city planning. We analyzed the impact of urbanization on white-tailed deer (Odocoileus virginianus) movement by studying 107 female deer that were captured and GPS-collared along an urbanization gradient in Durham and Orange Counties, North Carolina, from 2022 to 2024. We analyzed GPS collar data recorded at 2-hour intervals during the parturition season to assess the effects of land cover, proximity to anthropogenic features (e.g., roads), and time of day on white-tailed deer movement. We used hidden Markov movement models to classify deer into latent behavioral states and applied step selection functions to evaluate how deer navigate the landscape. This approach enabled us to quantify the proportion of time deer spent in each state across the urbanization gradient and understand how anthropogenic features affect deer movement. We determined that urbanization influenced deer movement and landscape use, with differing habitat selection across the gradient. Understanding the multifaceted effects of urbanization on deer movement, habitat selection, and behavior is important to inform management actions and predict responses of deer in urbanizing landscapes.

As urban sprawl increases, white-tailed deer have become more abundant across urban landscapes leading to increased deer encounters with residential fences. Deer-fence interactions can create dangerous situations for deer, first responders, and the public if a deer fails to jump over the fence effectively and becomes entangled in or on the fence. In order to reduce deer-fence conflicts, it is necessary to first understand the biomechanical processes deer use to cross vertical barriers. We conducted deer jumping trials in which captive deer crossed over vertical barriers (i.e., welded-wire fence panels) of varying heights while being recorded by high-speed cameras. We compared biomechanical measurements between successful and unsuccessful crossing attempts including joint angles, flight arc, and deer velocity through four phases of the jump: approach, take-off, suspension, and landing. We quantified biomechanical measurements among age, sex, and weight of deer relative to barrier heights. Our first sampling group consisted of 5 adult male deer (110 – 190 lb) and 30 total crossing attempts. Among all 30 attempts, 7 were successful, 9 were failures, and 14 did not attempt to cross. Across all biomechanical measures, it appears that the angle of the deer’s back at take-off, which affects the deer’s trajectory, most influences crossing success. We are conducting similar trials with 22 adult female deer. Altering the height and visual attributes of fencing (e.g., spacing and thickness of rails) will enable us to improve deer jumping success or entirely discourage deer from jumping barriers in order to reduce deer-fence conflicts.

White-tailed deer (Odocoileus virginianus) are key hosts for zoonotic diseases due to their susceptibility to pathogens such as SARS-CoV-2 (SCV2), Lyme Disease (Borrelia burgdorferi), and highly pathogenic avian influenza. Urban environments, with their high densities of both deer and humans, amplify the potential for disease spillover. In collaboration with USDA-WS, NPS, Washington D.C. Department of Energy and Environment, Fairfax County Park Authority (VA), and Montgomery Parks (MD), the University of Maryland’s URBANxNATURE and Applied Spatial Wildlife Ecology Lab are investigating human-deer disease transmission in urban settings. Deer are being captured using drop nets and anesthetized with BAM, 2024-2026. Nasal and oral swabs, blood samples, and ticks are being collected for testing. Out of 140 deer sampled in the winter of 2023-2024, 27 individuals tested positive for SCV2. Positive samples included ten nasal and six oral PCR positives from sharpshooting events, and eight sVNT seropositive results (five wildtype, three Omicron) from live trapping. Additionally, we confirmed the first longhorned ticks (Haemaphysalis longicornis) in Washington, D.C. These findings will inform an agent-based modeling framework to predict human-deer interaction hotspots, the context of such encounters, and the associated risk of airborne zoonotic disease transmission, contributing to urban wildlife management and public health strategies.

Urbanization presents a challenge for managing white-tailed deer (Odocoileus virginianus) due to the constraints it imposes on traditional methods of deer population management. Specifically, hunting effectiveness can be diminished due to decreasing parcel size, loss of huntable land, shifting landowner values, and restrictive local policies. Given the potential negative outcomes of unmanaged deer populations as landscapes urbanize, our objective was to describe how deer harvest susceptibility varied along an urban to rural gradient. Specifically, we: 1) quantified harvest probabilities for deer, 2) evaluated how these probabilities varied along an urbanization gradient based on percent impervious surface, percent huntable lands, sex, and age of deer, and 3) identified how harvest susceptibility varied throughout the hunting season. From 2022-2024, we tracked 72 male and 95 female white-tailed deer in Durham County, North Carolina, along an urban-rural gradient. Using GPS data, we quantified percent impervious surface and huntable lands within each individual's calculated home range. Results indicate that males were harvested more frequently than females across the gradient, with adults (≥ 2.5 years) being more susceptible than yearlings (1.5 years). The majority of harvest occurred after the peak conception date in the study area. Additionally, harvest probability declined as urbanness increased, regardless of sex or age. These results provide insight for wildlife managers in determining when and where harvest occurs along an urban-rural gradient, and whether to adjust strategies to meet management goals in increasingly urbanized landscapes.

Urbanization is expanding throughout the globe, creating urban-rural gradients and altering wildlife communities. While some wildlife populations decline as human presence increases, others such as white-tailed deer persist in areas with transitional habitats and increased urbanization. However, densities of white-tailed deer along urban-rural gradients are poorly understood leading to gaps in population information and management despite continued deer use. We used a spatially explicit capture-recapture framework (SCR) with fecal DNA to estimate deer densities along an urban-rural gradient in Durham County, North Carolina. Sampling occurred at 356 plots across 7 sites with percent impervious surface ranging from 1% (rural) to 60% (urban), and included public and private lands with 120 participating landowners. Field collection took place in February and March 2023 over 3 weeks using a cluster sampling design. We collected 642 fecal samples resulting in 491 genotypes (≥8 microsatellite markers, 1 sex-determining marker) of 380 unique deer (252M:127F). Based on SCR estimates, sampling site densities ranged from

Rangelands are often managed for cattle production and wildlife. Understanding the effects of cattle on wildlife relative to other factors, such as precipitation, is key to effective multiuse management. We experimentally manipulated cattle management on East Foundation’s San Antonio Veijo Ranch in South Texas where white-tailed deer are not exposed to harvest or supplemental feed. We measured recruitment indices using evidence of lactation in autumn from 284 adult female deer captured from 2011-2023 and known fate survival to 12-weeks of 90 neonates monitored during 2020-2023. We characterized capture locations of adult females and birth sites of neonates based on landscape attributes, precipitation, and cattle management. We fit generalized linear mixed models predicting the lactation status (yes or no) as a function of these covariates. We fit Cox-proportional hazards models to predict mortality hazard of neonates as a function of the same predictors. We found the presence of cattle during the fawning season (June-August) reduced the probability of lactation in adult females and increased the odds of neonate mortality. We also found both recruitment indices increased strongly with spring rain and moderately with brush density. Our results demonstrate a benefit of the rotational grazing treatment, such that deer recruitment improved where cattle were absent during the fawning season. While rainfall patterns strongly influenced recruitment, manageable factors including cattle grazing and brush density offer potential approaches to manipulate deer recruitment. Our results highlight the utility of managing these factors to achieve deer recruitment objectives.

Unmanned aerial vehicles, or drones, have become increasingly important in the monitoring and management of white-tailed deer (Odocoileus virginianus) particularly when used alongside thermal imaging sensors. Thermal drones have successfully been used for fawn capture, deer density estimation, harvested deer recovery, and other management practices, and thermal drones have been found to be both accurate and precise for deer density estimation given proper flight planning. Drones as a tool for deer monitoring and management improve upon manned aircraft in terms of costs and associated risks, but thermal drones nonetheless suffer from limitations related to battery life, signal range, line of sight requirements, and sensitivity to environmental conditions among other factors. Building on our previous work evaluating the precision and accuracy of deer density estimates gathered via drones, this presentation will discuss the current state of commercially available thermal drone technology, costs and considerations associated with implementing this technology, and lessons learned from our work. We will detail recommended flight parameters, drone models, and sensors as well as the future of this technology and its integration into deer monitoring and management. This discussion provides fundamental information for wildlife managers and researchers seeking to implement this rapidly evolving technology into their own work.

Early detection is critical to managing CWD effectively and the average number of national samples needed for adequate testing annually is increasing. We surveyed state wildlife agencies to determine their budget dedicated to CWD surveillance, monitoring and testing, the number of samples tested, average wait time for results, and if sampling goals were met in 2019 and 2024. We also asked where CWD samples are collected from and if replacement tags are offered to hunters who harvest a CWD positive deer. Since 2019, agencies have allocated an additional $13 million nationally for CWD; a 128% increase. Contributing to this additional cost is a 38% increase in sampling efforts from 2019 to 2023, with 43 states testing nearly 250,000 samples. Despite the increasing cost and manpower required for testing, average wait time for results decreased from 36 to 29 days since 2019, with at least four states offering results in one week. Increased surveillance has forced agencies to diversify how samples are collected and agencies reported nearly ten different sources, with clinically suspect deer the most popular (96%). Forty-two states rely heavily on hunter harvested deer with 18 states offering replacement tags to hunters who take a CWD positive animal. Fortunately, 26 states met their sampling goals in 2023, with at least eight more reaching their goals in individual CWD surveillance zones or counties. Our results shed light on the drain that CWD has on wildlife agency resources and the intensive and opportunistic sampling that is crucial to manage the disease.

Efforts to standardize terminology are valuable across scientific disciplines for improving clarity, enabling consistent evaluation of research findings, reducing confusion, and improving the accuracy of scientific communication. Chronic wasting disease (CWD) has become a marked and expanding threat to cervid health and North American conservation. The Surveillance Optimization Project for CWD (SOP4CWD) was implemented to provide quantitative modeling and data warehousing tools to partnering wildlife agencies to improve surveillance efficiency in free-ranging populations. This interdisciplinary collaboration recognized a need for a standardized glossary of CWD-related epidemiology, disease management, and mathematical modeling terminology to effectively unite monitoring and control efforts across scientific disciplines and managerial jurisdictions. Using an expert elicitation approach, we compiled a comprehensive list of terms relevant to CWD and standardized definitions agreed upon simultaneously by persons with disease, statistical, and deer ecology expertise. We augmented the glossary with terms commonly found in the academic literature surrounding CWD. The final glossary will facilitate consistency in communication and promote coordination of CWD surveillance, research, management, and mitigation across vast jurisdictional boundaries.

Scavengers can impact the geographic spread of pathogens through complex interactions that can either decrease or increase the risk of transmission. Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy fatal to cervids and has been detected throughout much of the United States and internationally. Chronic wasting disease prions have long environmental persistence, and some scavengers have been shown to pass infectious CWD prions through their digestive tracts. We designed a study in a CWD-endemic area of northwestern Arkansas to determine which scavengers routinely feed on white-tailed deer carcasses and may be involved in movement of CWD prions. Using videos from game cameras, we recorded species that visited white-tailed deer carcasses and calculated abundance, presence duration, and feeding rate. American crows had the greatest number of individuals per video (5.33, 95% CI: 3.88 – 7.32), followed by turkey vultures (3.03, 2.21 – 4.16), and black vultures (2.94, 2.14 – 4.04). Black vultures had the longest bout duration in minutes (10.46, 8.01 – 13.67), followed by bald eagles (9.00, 6.88 – 11.77) and turkey vultures (8.45, 6.47 – 11.04). Bald eagles (50%, 38 – 62%), black vultures (49%, 40 – 58%), and American black bears (45%, 33-56%) spent the greatest proportion of time feeding. Species rank varied across metrics but the average of the three behavioral measurements indicated that black vultures, bald eagles, and turkey vultures had the greatest potential to ingest and potentially move CWD prions. Our research highlights the need to experimentally evaluate more avian scavengers for the potential to shed infectious prions.

Chronic Wasting Disease (CWD) poses a significant challenge to wildlife disease management, driven by the highly infectious nature of prions, the potential for both direct and indirect transmission routes, and the prolonged progression of the disease in infected cervids. These features greatly complicate surveillance and control efforts in both free-ranging and captive cervid populations. Recent advances in Real-Time Quaking-Induced Conversion (RT-QuIC) assays and related technologies are contributing to a paradigm shift in CWD surveillance. Due to its remarkable sensitivity and specificity, RT-QuIC offers the detection of prions in a variety of environmental and biological samples that were previously untestable. Simultaneously, agent-based epidemiological modeling informed by CWD biology and cervid demographics (e.g., OvCWD) offers a valuable framework for designing and optimizing novel RT-QuIC-based surveillance strategies. We present three innovative RT-QuIC testing applications that enhance CWD surveillance: (1) detection of CWD prions in cervid saliva on non-porous surfaces, (2) monitoring prions in environmental matrices such as soil and water near herd congregation sites, and (3) testing of skeletal remains years after deposition. Surveillance data derived from both wild and captive white-tailed deer populations across these three areas are summarized. We show how these three approaches can be used strategically with agent-based epidemiological models to guide efforts to prevent disease spread, identify and remediate environmental prion reservoirs, and ultimately improve the sustainability of cervid populations. Our findings underscore the potential of integrating RT-QuIC surveillance with epidemiological modeling to transform CWD management through proactive, data-driven strategies.

Chronic wasting disease (CWD) is a fatal prion disease affecting members of the Cervidae family and is present in both wild and captive cervid populations across the United States. CWD continues to spread among captive facilities, with new positive facilities being detected each year. CWD can quickly become established in these facilities due to the close and prolonged contact among deer and repeated exposure to infected individuals or contaminated environments. Early detection is crucial for managing CWD; however, identifying a rare event like CWD introduction in a large population presents significant challenges. Furthermore, the number of samples required to achieve a high level of confidence in detecting CWD increases for low prevalence scenarios, making it particularly difficult to detect a single infected deer in a captive facility. Thus, CWD often remains undetected in the early phase of the outbreak, mainly because of the logistical constraints on wildlife agencies' ability to match the sample size targets.
To address these challenges, we developed an agent-based modeling approach that enhances the estimation of CWD detection probability in captive deer facilities. Specifically, we define CWD detection probability as the confidence in identifying the single infected deer within a population, based on a given number of samples tested over the course of a year. Our modeling approach integrates CWD testing records from captive deer facilities, along with herd size, composition, and individual deer transfer histories, to quantify the likelihood of undetected CWD within a facility. These annual detection probability estimates provide a measure of confidence in identifying a single CWD-infected deer within a population, based on the number of deer that tested negative throughout the year. This approach improves the effectiveness of CWD surveillance by enabling the prioritization of surveillance efforts across captive facilities, using the model-derived quantitative metric of detection probability. By refining this estimation process, we provide improved surveillance approach and inform better CWD management strategies in captive cervid populations.

Chronic wasting disease (CWD) is a fatal prion disease of cervids, considered to be one of the greatest threats to white-tailed deer populations. Effective management for CWD hinges on understanding how abundance, survival and recruitment are affected by the disease. Using 3 years of data from GPS collars, radio telemetry, trail cameras, and CWD testing of both live and deceased deer, we investigated the effects of CWD on population demographics for a white-tailed deer population in Arkansas’ CWD management zone. We analyzed our data using an integrated hierarchical model in a Bayesian framework to estimate survival, recruitment, movement and disease transmission across 3 study sites with different levels of CWD prevalence. Sample CWD prevalence from both ante- and postmortem sample testing was >20%. Deer that tested positive for CWD had lower annual survival and reproductive rates than presumed negative deer. Populations with the highest prevalence of CWD had lower densities and higher female to male sex ratios. Our results provide insights into the dynamics of CWD in the Southeastern United States and suggest CWD is working in concert with environmental factors to alter age structure and reduce population abundance.

An informal discussion about CWD management.