Chuck Anderson, Head of Mammals Research
description: Chuck Anderson Mammals Research Section Leader Current or Recent Research Projects Mitigating Impacts of Energy Development on Piceance Basin Mule Deer Populations Areas of Interest and Expertise My research focuses on large mammal ecology and management, with an emphasis on population dynamics, population monitoring, and population genetics. Streaming Videos Wild Science: Mule Deer in the Piceance Basin Select Publications Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., E. H. VanNatta, J. D. Holbrook, and G. Bastille-Rousseau. 2025. Hierarchy in structuring of resource selection: understanding elk selection across space, time, and movement strategies. Ecology and Evolution 15:e71097. https://doi.org/10.1002/ece3.71097 Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., and G. Bastille-Rousseau. 2025. Drivers of spring migration phenology in Rocky Mountain elk. Scientific Reports 15:7807. https://doi.org/10.1038/s41598-025-91947-4 Hurley, M. A., C. R. Anderson Jr., T. D. Forrester, and J. A. Gude. 2023. Carnivore-prey relationships. Pages 125-139 in J. R. Heffelfinger and P. R. Krausman, editors. Ecology and management of black-tailed and mule deer of North America. CRC Press, Boca Raton, Florida, USA.​ ​Johnston, D. H., and C. R. Anderson Jr. 2023. Plant and mule deer responses to pinyon-juiper removal by three mechanical methods. Wildlife Society Bulletin 47:e1421​. https://doi.org/10.1002/jwmg.22110​ Bonar, M., S. J. Anderson, C. R. Anderson Jr, G. Wittemyer, J. M. Northrup, and A. B. Shafer. 2022. Genomic correlates for migratory direction in a free-ranging cervid. Proceedings of the Royal Society B 289:20221969. https://doi.org/10.1098/rspb.2022.1969​ Johnston, D. H., C. R. Anderson Jr., R. D. Applegate, L. Bailey, E. Cooch, J. Feiberg, A. B. Franklin, R. J. Gutiérrez, K. V. Miller, J. D. Nichols, N. D. Niemuth, D. Otis, C. A. Ribic, M. M. Rowland, and T. L. Shaffer. 2021. Editor's Message: A perspective on the …
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Jake Ivan, Senior Wildlife Research Scientist
description: Jake Ivan Senior Wildlife Research Scientist, Species of Conservation Concern Current or Recent Research Projects Snowshoe Hare Response to Silvicultural Treatments Monitoring Canada Lynx in Colorado Mammal and Breeding Bird Response to Bark Beetle Outbreaks Areas of Interest and Expertise My research focuses on estimating wildlife population parameters and forest carnivore ecology, conservation and monitoring. Streaming Videos Catching pine Lynx: shadows of the forest Snowshoe hare Snowshoe hare releases Snowshoe hare trapping, collaring and release Select Publications Bosco-Lauth, A. M., S. M. Porter, R. M. Maison, K. A. Fox, J. M. Marano, J. S. Ivan, K. Griffin, M. Quilici, and J. J. Root. 2025. Rabbit Hemorrhagic Disease Virus 2 experimental infection in snowshoe hares (Lepus americanus). Journal of Wildlife Diseases 61:674-684. doi: 10.7589/JWD-D-24-00141 Devarajan, K. [numerous authors], J. S. Ivan, [numerous authors]. 2025. When the wild things are: defining mammalian diel activity and plasticity. Science Advances 11:eado3843. DOI: 10.1126/sciadv.ado3843 Ivan, J. S. 2024. Canada Lynx (lynx Canadensis). Pages 129-152 in J. E. Cartron and J. K. Frey, Eds. Wild Carnivores of New Mexico. University of New Mexico Press. Hooten, M. B., M. R. Schwob, D. S. Johnson and J. S. Ivan. 2024. Geostatistical capture-recapture models​​. Spatial Statistics 59:100817. doi.org/10.1016/j.spasta.2024.100817​ Squires, J. R., Olson, L. E., Ivan, J. S., McDonald, P. M., and Holbrook, J. D. 2024. Anthropogenically protected but naturally disturbed: a specialist carnivore at its southern range periphery. Biodiversity and Conservation. https://doi.org/10.1007/s10531-024-02978-8 Hooten, M. B., M. R. Schwob, D. S. Johnson, and J. S. Ivan. 2023. Multistage hierarchical capture-recapture models. Environmetrics 34:e2799. doi.org/10.1002/env.2799 Ivan, J. S., E. S. Newkirk, and B. D. Gerber. 2023. Differential impacts of spruce beetle outbreaks on snowshoe hares and red squirrels in the sout…
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Effects of Habitat Treatments on Mule Deer Survival and Health During the Winter
description: Led By: Eric Bergman Study Area: Uncompahgre Plateau and adjacent valleys in southwest Colorado Project Status: Completed Research Objectives: To evaluate the impacts of large-scale vegetation habitat treatment on mule deer survival and health during the winter. To develop habitat management strategies for the benefit of deer To put research results into context with historical records and recent declines in mule deer herd populations. Project Description: Mule deer populations in Colorado have shown dramatic fluctuations since the 1960s. Beginning in the 1990s, some western Colorado mule deer herds demonstrated the most recent decline. For many decades, wildlife managers have used habitat management as a way to increase the health and survival of mule deer, but the effect of these efforts had not yet been evaluated. Evaluating these efforts was the focus of this 4-year study to measure the health and survival of mule deer herds during the winter months in areas treated with different levels of habitat management. In the course of this study, researchers monitored fawn survival, mule deer body conditions, and population densities in areas with different levels of habitat management. Habitat treatment varied from mechanical disturbance in the form of hydro-axe clearing and roller-chopping of late seral stage pinyon-juniper forests, chemical control of weeds, and reseeding with desirable mule deer browse species. The results of this study will help managers select the most effective habitat treatments to apply to mule deer winter ranges. Associated Publications Bergman, E.J., C.J. Bishop, D.J. Freddy, G.C. White and P.F. Doherty. 2014. Habitat management influence overwinter survival of mule deer fawns in Colorado. Journal of Wildlife Management 78(3):448–455. Bergman, E.J. 2013. Evaluation of winter range habitat treatments on overwinter survival, density, and body condition of mule deer. Dissertation, Colorado State University, Fort Collins, Colorado, USA, 137pp. Wa…
creator: Bergman, Eric J.
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Eric Bergman, Mammals Research Scientist
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Ellen Brandell, Wildlife Research Scientist
description: Current or Recent Research Projects Wolf ecology Wolf habitat selection and movement during re establishment in Colorado Wildlife management Statistical estimation of wolf abundance Quantifying the effects of management practices and disease on wildlife harvest Wolf-livestock dynamics Identifying and examining potential nonconsumptive effects of wolves on cattle Predator-prey dynamics Examining wolf and hunter effects on elk movement, space use, and aggregation patterns Quantifying conditions under which predators influence prey diseases​ Areas of Interest and Expertise​ My background is in terrestrial wildlife ecology with a focus on carnivores (primarily gray wolves) and infectious diseases. I am interested in many facets of wildlife ecology, especially social behaviors, predator-prey interactions, population dynamics, and disease dynamics. My work intersects wildlife ecology, wildlife management, statistics, and disease ecology.​ Select Publications Draper, J. P., E. E. Brandell, J. Isabelle, C. Jacques, C. McCoy, E. Michel, D. J. Storm, C. Ott-Conn, B. Wojcik, W. C. Turner, and D. P. Walsh. 2025. Doe diligence: a regional analysis of antlerless deer harvest regulations in the Midwestern United States of America. PLoS One, 20(6): p.e0324708. https://doi.org/10.1371/journal.pone.0324708 Inzalaco, H. N. t., E. E. Brandell, S. P. Wilson, M. Hunsaker, D. R. Stahler, K. Woelfel, D. P. Walsh, T. Nordeen, D. J. Storm, and S. S. Lichtenberg. 2024. Detection of prions from spiked and free-ranging carnivore feces. Scientific Reports 14:3804. doi.org/10.1038/s41598-023-44167-7 Cubaynes, S., E. E. Brandell, D. R. Stahler, D. W. Smith, E. S. Almberg, S. Schindler, R. K. Wayne, A. P. Dobson, B. M. vonHoldt, D. R. MacNulty, P. D. Cross, P. J. Hudson, and T. Coulson. 2022. Disease outbreaks select for mate choice and coat color in wolves. Science 378:300–303; DOI: 10.1126/science.abi8745 Meyer, C. J., K. A. Cassidy, E. E. Stahler, E. E. Brandell, C. B. Anton, D. R. Stahler, and …
creator: Brandell, Ellen
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Mat Alldredge, Senior Wildlife Research Scientist
description: Senior Wildlife Research Scientist, Carnivores ​ Current or Recent Research Projects Using Non-Invasive Genetic Sampling to Estimate Mountain Lion and Bobcat Abundance, Age Structure and Diet Mountain Lion Demographics and Human Interactions Along the Urban-Exurban Front Range Areas of Interest and Expertise My research interest focuses on large carnivore and ungulate ecology, population parameter estimation, habitat use, avian ecology and population sampling. Streaming Videos Mountain lions in Colorado – a 4 part series Series Trailer Part 1: Mountain Lion Biology & Historical Perspective Part 2: Mountain Lion Habitat & Human Expansion Part 3: Hunting Part 4: What to do if you encounter a mountain lion Colorado Mountain Lions (all 4 videos combined) Select Publications Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., E. H. VanNatta, J. D. Holbrook, and G. Bastille-Rousseau. 2025. Hierarchy in structuring of resource selection: understanding elk selection across space, time, and movement strategies. Ecology and Evolution 15:e71097. https://doi.org/10.1002/ece3.71097 Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., and G. Bastille-Rousseau. 2025. Drivers of spring migration phenology in Rocky Mountain elk. Scientific Reports 15:7807. https://doi.org/10.1038/s41598-025-91947-4 Venumière-Lefebvre, C. C., H. E. Johnson, S. W. Breck, M. W. Alldredge, and K. R. Crooks. 2025. Bears avoid residential neighborhoods in response to the experimental reduction of anthropogenic attractants. Frontiers in Ecology and Evolution 13:1657106. doi: 10.3389/fevo.2025.1657106 Fountain-Jones, N. M., S. Kraberger, R. B. Gagne, D. R. Trumbo, P. E. Salerno, W. C. Funk, K. Crooks, R. Biek, M. W. Alldredge, K. Logan, G. Baele, S. Dellicour, H. B. Ernest, S. VandeWoude, S. Carver, and M. E. Craft. 2021. Host relatedness and landscape connectivity shape pathogen spread in the puma, a large secretive carnivore​. Communications Biology 4:12. doi: …
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Mitigating Impacts of Energy Development on Piceance Basin Mule Deer Populations
description: Lead Researcher Chuck Anderson Study Area Piceance Basin — located between the cities of Rangely, Meeker and Rifle in northwest Colorado. Project Status Completed: Final progress report Research Objectives To determine the effects of energy development on mule deer behavior and population trends. To determine if habitat improvements benefit mule deer populations exposed to energy development activities. To identify energy development practices that will minimize impacts to mule deer populations. ​​ Project Description Energy development in western Colorado has the potential to negatively impact mule deer populations. These impacts include habitat fragmentation and destruction, increased deer-vehicle collisions, increased noise levels, and more. Thus, this project aims to identify habitat improvements and energy development practices that will sustain mule deer populations for future recreational and ecological values. Researchers selected the Piceance Basin as the project's study area because the basin contains some of the largest natural gas reserves in North America. Piceance is also home to one of Colorado's most important mule deer populations. During this long-term project, researchers will track mule deer habitat use and behavior, observe animal health throughout the winter season, monitor fawn survival and estimate mule deer populations in the study area. Finally, researchers will determine the success of different habitat improvements in reducing disturbances caused by energy development and in improving winter condition of mule deer. The results of this project will show wildlife managers and energy developers if it is ecologically and financially valuable to mitigate disturbances in highly developed areas versus focusing efforts in nearby less or non-impacted areas. Collaborators for this multi-million dollar project include BLM, Colorado State University, Idaho State University, and multiple energy corporations and sportspeople's organizations. Resources:…
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Gray Wolf Reintroduction pdfs
description: PDF files for Gray Wolf Reintroduction: Resources digital collection page.
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Nathaniel Rayl, Wildlife Research Scientist
description: Wildlife Researcher, Ungulates/Carnivores Current or Recent Research Projects ​Evaluating Factors Influencing Elk Recruitment in Colorado Assessing Responses of Elk to Human Recreation in Colorado Spatiotemporal Effects of Human Recreation on Elk Behavior Areas of Interest and Expertise My research focuses on large mammal ecology and management, with an emphasis on spatial ecology, population dynamics, and predator-prey interactions. Streaming Videos Emblems of the West Select Publications Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., E. H. VanNatta, J. D. Holbrook, and G. Bastille-Rousseau. 2025. Hierarchy in structuring of resource selection: understanding elk selection across space, time, and movement strategies. Ecology and Evolution 15:e71097. https://doi.org/10.1002/ece3.71097 Crews, S., N. D. Rayl, M. W. Alldredge, E. J. Bergman, C. R. Anderson Jr., and G. Bastille-Rousseau. 2025. Drivers of spring migration phenology in Rocky Mountain elk. Scientific Reports 15:7807. https://doi.org/10.1038/s41598-025-91947-4 Bastille-Rousseau, G., S. A. Crews, E. B. Donovan, M. E. Egan, N. T. Gorman, J. B. Pitman, A. M. Weber, E. M. Audia, M. R. Larreur, H. Manninen, S. Blake, M. W. Eihholz, E. Bergman, and N. D. Rayl. 2024. A multi‐property assessment of intensity of use provides a functional understanding of animal movement. Methods in Ecology and Evolution 15:345-357. doi.org/10.1111/2041-210X.14274​ Egan, M. E., N. T. Gorman, S. Crews, M. W. Eichholz, D. Skinner, P. E. Schlichting, N. D. Rayl, E. J. Bergman, E. H. Ellington, and G. Bastille-Rousseau. 2024. Estimating encounter-habitat relationships with scale-integrated resource selection functions. Journal of Animal Ecology 93:1036-1048. https://doi.org/10.1111/1365-2656.14133 Rayl, N.D., J.A. Merkle, K.M. Proffitt, E.S. Almberg, J.D. Jones, J.A. Gude, and P.C. Cross. 2021. Elk migration influences the risk of disease spillover in the Greater Yellowstone Ecosystem. Journal of Animal Ecology…
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Kayla Friedrich, Program Assistant
description: Mammals Research Section Program Assistant Responsibilities Regulatory and procedural compliance processes for Colorado Parks and Wildlife Animal Care and Use Committee, financial support, publishing support, and event planning. Education University of Alaska Fairbanks Areas of Interest and Expertise "I have always been the person who looks at a chaotic, inefficient process and thinks, "How can we make this run better?" Where others struggle with organization, I thrive. My expertise lies in supporting program growth by effectively tracking budgets, streamlining outdated and inefficient processes, and innovating fresh ideas. There is nothing more rewarding to me than seeing a project through from start to finish. I love managing the back-end logistics, keeping everything organized, and ensuring deadlines are met." Current or Recent Positions Program Assistant II, Mammals Research Program, 2026-Present Administrative Assistant III, Habitat Partnership Program, 2024-2026 Administrative Assistant III, Vega State Park, 2022-2024 ​Contact Information 711 Independent Ave. Grand Junction, CO 81505