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Deer and CWD Scientific Publications

collared deer

The DNR conducts research on deer and deer populations to help inform deer management. Research priorities have been identified by management programs in collaboration with DNR research staff that address the most pressing information needs to guide deer and chronic wasting disease (CWD) management in the future. 

DNR research has focused on:

  • Deer survival in northern forests and central farmlands
  • Habitat and movement patterns across Wisconsin's diverse landscapes
  • Improved population monitoring
  • Incorporation of new information from hunters and the public
  • Improved understanding of how deer are responding to changing hunting patterns, land use, disease exposure and climate

The centerpiece of DNR deer and CWD research is the Southwest Wisconsin CWD, Deer and Predator Study, which has an ultimate project goal of determining the impact of CWD on deer populations. Still ongoing, this complex project has spurred numerous new research projects, much of which have already been published. Research across such diverse topics benefit from cooperation across agencies and disciplines. The DNR has partnered with UW-Madison, the U.S. Geological Survey (USGS) and the Wisconsin Cooperative Wildlife Research Unit (WCWRU) to maximize the value of this work, greatly increasing our research capacity and productivity.

Below is a list of scientific publications resulting from recent deer and CWD research efforts, including related papers published by collaborators who received DNR funding or support. Current and former DNR staff are indicated in bold; an asterisk indicates graduate or post-doctoral scientists supported by the DNR. Note that this list will be periodically updated as new research is published. 

 

Ticks harbor and excrete chronic wasting disease prions (2023)

Inzalaco, H.N.*, F. Bravo-Risi, Morales, R., Walsh, D.P., Storm, D.J., Pedersen, J.A., Turner, W.C., Lichtenberg, S.S.*

Key Findings:

  • Blacklegged ticks (deer ticks) can ingest CWD prions by consuming blood from CWD-infected whitetail deer.
  • Ticks can harbor infectious doses of CWD prions and be eaten by deer during social grooming sessions, a common tick defense strategy for deer.
  • It is not clear if CWD transmission via consumption of ticks carrying CWD prions is occurring in the wild, but ticks present a plausible pathway for transmission.

 

Informing Surveillance through the Characterization of Outbreak Potential of Chronic Wasting Disease in White-Tailed Deer (2022)

Hanley, B. J., Carstensen, M., Walsh, D. P., Christensen, S. A., Storm, D. J., Booth, J. G., Guinness, J., Them, C. E., Ahmed, M. S., & Schuler, K.

Key Findings:

  • Examines some of the conditions that lead CWD to either become an epidemic or fail to spread.
  • Modeling indicates CWD transmission is unlikely to be strictly density-dependent and that environmental transmission is likely important.
  • The developed model can be useful to identify areas of potential CWD outbreak and target surveillance efforts.

 

Diagnostic testing of chronic wasting disease in white-tailed deer (Odocoileus virginianus) by RT-QuIC using multiple tissues (2022)

Burgener, Kate R.*, Lichtenberg, S.S.*, Lomax, A., Storm, D.J., Walsh, D.P., Pedersen, J.A.

Key Findings:

  • RT-QuIC prion amplification assay is a new, highly sensitive procedure to detect the presence of CWD.
  • This study demonstrated that RT-QuIC is effective at detecting prion in non-traditional tissues, such as skin, to detect prions in both live and dead deer.
  • Sensitive live deer (antemortem) CWD testing is especially useful for research applications.
  • Effective postmortem (after death) sampling using small, easily accessible tissues may simplify sample preparation by hunters and decrease disposal and overall CWD testing costs if this diagnostic technique can be sufficiently scaled up and achieve regulatory approval.

 

A call to action: Standardizing white-tailed deer harvest data in the Midwestern United States and implications for quantitative analysis and disease management (2022)

Brandell Ellen E.*, Storm D.J., Van Deelen T.R., Walsh, D.P., Turner, W.C.

Key Findings:

  • Data collection on white-tailed deer from hunting and harvest measures vary across states.
  • Standardization of data collection practices across state lines could lead to more comprehensive wildlife and disease management.
  • Recommendations were developed to streamline and standardize hunter and harvest data collection.

 

Chronic wasting disease and implications for cervid populations (2019)

Ketz, A. C.*, Storm, D. J., & Samuel, M.

Key Findings:

  • The early phase of CWD is characterized by slowly increasing prevalence and geographic spread.
  • CWD spread eventually accelerates and leads to survival and recruitment declines that drive population reductions.
  • The threshold for population impacts depends on many factors, including species-specific demography, genetics and transmission.

 

Chronic wasting disease in white-tailed deer: infection, mortality, and implications for heterogeneous transmission (2016)

Samuel, M. D. & Storm, D. J.

Key Findings:

  • Using CWD surveillance data, models were made to estimate the rate of infection and associated mortality of CWD for white-tailed deer in Wisconsin and Illinois.
  • Findings indicated that adult male deer have a higher risk of CWD infection and disease mortality when compared to female deer, resulting in CWD prevalence that was two times higher in adult males.

 

 

Assimilating ecological theory with empiricism: Using constrained generalized additive models to enhance survival analyses (2023)

Ketz, A. C.*, Storm, D. J., Barker, R. E., Apa, A. D., Oliva-Aviles, C., & Walsh, D. P.

Key Findings:

  • An improved approach to survival analysis was developed that integrates ecological information for a species, introducing a new tool for ecologists.
  • This modeling approach is more flexible and interpretable than other models, providing a method to account for drivers of survival, both intrinsic (e.g., age effects) and extrinsic factors (e.g., changing seasons).
  • Data on female deer survival from the Southwest Wisconsin CWD study contributed to the development of this new modeling approach; survival estimates for female deer surviving up to one year of age was 54% for the study sample.

 

Cause of death, pathology, and chronic wasting disease status of white-tailed deer (Odocoileus virginianus) mortalities in Wisconsin, USA (2022)

Gilbertson, M.L.J.*, Brandell, E.E.*, Pinkerton, M.E., Meaux, N.M., Hunsaker, M.*, Jarosinski, D., Ellarson, W., Walsh, D.P., Storm, D.J., Turner, W.C.

Key Findings:

  • 42% of deer that were collared as part of the Southwest Wisconsin CWD, Deer and Predator Study and later died tested positive for CWD.
  • The probability of a deer testing positive for CWD increased with age before decreasing among older individuals.
  • CWD was closely associated with emaciation, loss of bone marrow fat, ectoparasites (lice and ticks) and bronchopneumonia.
  • Female deer were significantly more likely to die with end-stage CWD than males.

 

White-Tailed Deer, Weather and Predation: A New Understanding of Winter Severity for Predicting Deer Mortality (2021)

Norton, A. S.*, Storm, D. J., & Van Deelen, T. R.

Key Findings:

  • In forested and agricultural areas, the timing of the winter-to-spring transition is more important for deer survival than sustained cold temperatures.
  • Results suggest changes in predator abundance may have a minor influence on overwinter survival compared to winter weather.
  • When lacking survival estimates from collared deer, managers can use the model created from this study to predict annual winter effects on deer survival.

 

Cause-specific neonatal mortality of white-tailed deer in Wisconsin, USA (2017)

Warbington, C. H.*, Van Deelen, T. R., Norton, A. S.*, Stenglein, J. L., Storm, D. J. & Martin, K. J. 

Key Findings:

  • In the northern forest, predation (mostly from black bears, bobcats, and coyotes) was the most common cause of mortality, and 35-60% of fawns died before September 1 of each year.
  • In the eastern farmland, 29-35% of fawns died before September 1, primarily due to natural causes such as starvation.
  • Notably, despite the low levels of predation in the eastern farmland, about one-third of fawns died; this demonstrates predators do not entirely dictate fawn survival and some amount of fawn mortality is to be expected.

 

Using expert knowledge to incorporate uncertainty in cause-of-death assignments for modeling of cause-specific mortality (2017)

Walsh, D. P., Norton, A.S.*, Storm, D. J., Van Deelen, T. R., & Heisey, D. M. 

Key Findings:

  • When determining the cause of death for radio-collared deer, there is often limited evidence about what killed the animal.
  • This paper describes statistical methods that explicitly incorporate expert knowledge and the associated uncertainty to estimate the cause of death when there is less-than-perfect evidence about how an animal died.
  • Comparing this method to traditional approaches suggests that to ensure thorough and accurate conclusions, it is critical to explicitly incorporate expert knowledge in statistical methods.

 

Left truncation criteria for survival analysis of white-tailed deer (2016)

Norton, A. S.*, Storm, D. J., Watt, M. A., Jacques, C. N., Martin, K. & Van Deelen, T. R.

Key Findings:

  • Often, in deer survival studies, researchers will ignore deaths within 2-4 weeks of collaring on the assumption that the capture event itself could temporarily increase the chance of death.
  • This practice was evaluated by analyzing mortality data for 1,001 collared white-tailed deer.
  • Mortality was not elevated for the two weeks immediately following capture, suggesting that the practice of ignoring mortality within two weeks of collaring is unnecessary.

 

 

Agricultural land use shapes dispersal in white-tailed deer (Odocoileus virginianus) (2022)

Gilbertson, M.L.J.*, Ketz, A.C.*, Hunsaker, M.*, Jarosinski, D., Ellarson, W., Walsh, D.P., Storm, D.J., Turner, W.C.

Key Findings:

  • Juvenile male deer were most likely to disperse (64.2%) and typically avoided agricultural land, quickly moving from forested cover to forested cover and seeking areas near rivers and streams.
  • Dispersal distances were typically short, especially in fall, but longer dispersal distances were observed if an individual's natal range had a higher amount of agricultural land vs forest.
  • Land use by deer should be considered when predicting the risk of CWD spreading to new areas.

 

Behavioral Flexibility Facilitates Use Of Spatial and Temporal Refugia During Variable Winter Weather (2022)

Gilbert, Neil A.*, Stenglein, J.  L., Van Deelen, T. R., Townsend, P. A., and B. Zuckerberg

Key Findings:

  • Snapshot Wisconsin data were used over two winters to determine how deer changed their behavior during extreme cold and warm events.
  • During frigid temperatures, deer became more active during the day and used conifer-dominated landscapes, while on abnormally warm winter days, deer were more active at night and used more deciduous landscapes.
  • Deer demonstrated stronger responses to abnormal temperatures later in winter.
  • For more peer-reviewed papers that use Snapshot Wisconsin trail camera data, please see Snapshot Wisconsin's Scientific Publications.

 

Habitat and weather influence body condition in white-tailed deer, Wisconsin, USA (2022)

McGraw, A.M., Bronson, D.R., Pearson, T., Storm, D.J.

Key Findings:

  • Hunters measured several body condition indicators for 795 deer during September-December 2016-2018.
  • The timing of spring green-up can affect deer health that can be consistently observed the following fall, such as heart fat and antler size.
  • Findings demonstrate that the hunting public can contribute large-scale, cost-effective and quality data to deer monitoring and research.

 

Influence of landscape on the dispersal of yearling male white-tailed deer in Wisconsin (2017)

Peterson, B. E.*, Storm, D. J., Norton, A. S.*, & Van Deelen, T. R.

Key Findings:

  • Among the two study areas, dispersal directions were unbiased in the heavily forested area but had a southeastern bias in the farmland area.
  • The effects of movement barriers (roads, rivers and cities) differed between study areas, suggesting that natural and man-made features can influence disease transmission and gene flow that occur as a result of dispersal.
  • Results suggest dispersal models should consider movement barriers in more developed landscapes and that barriers could be used to inform the designation of management units.

 

A Phenology of Fear: Investigating Scale and Seasonality in Predator-Prey Games Between Wolves and White-tailed Deer (2023)

Clare, J.D.J.*, Zuckerberg, B., Liu, N., Stenglein, J.L., Van Deelen, T.R., Pauli, J.N., and P.A. Townsend

Key Findings:

  • An entire year of Snapshot Wisconsin data was used to understand fine-scale spatial and seasonal changes in the use of landscape by deer and wolves.
  • Deer responses to the presence of wolves varied depending on snow, vegetation growth and time of year.
  • Deer were more likely to avoid areas recently used by wolves in the spring and fall, while less likely to avoid these areas in winter.
  • Deer spent time in rich foraging areas recently used by wolves in summer, reducing predation risk by increasing their vigilance.

 

Do the antipredator strategies of shared prey mediate intraguild predation and mesopredator suppression (2016)

Clare, J. D. J.*, Linden, D. W., Anderson, E. M. & MacFarland, D. M. 

Key Findings:

  • In one study, lagomorphs (hares, rabbits and pika) did not appear to avoid coyotes, and fox detection probability was lower as coyote abundance increased.
  • White-tailed deer appeared to avoid areas of increased wolf use, and coyote detection probability was not reduced at sites where wolves occurred.
  • Findings suggest that suppression of mid-level predators (e.g., coyotes) by larger carnivores (wolves) may depend on the behavior of their shared prey.