Breck, Stewart

Dr. Stewart W. Breck

Photo of Dr. Stewart Breck Dr. Stewart W. Breck,
Research Wildlife Biologist

Dr. Stewart Breck is a researcher for the USDA-National Wildlife Research Center and his research is focused on carnivore ecology and behavior and minimizing conflict between carnivores and people. Studies include testing nonlethal methods for preventing conflict, measuring the impact of carnivores on livestock, influence of urban environments on carnivore ecology, and population biology and behavioral ecology of carnivores.

NWRC Research Project: Developing Control Methods, Evaluating Impacts, and Applying Ecology, Behavior, Genetics, and Demographics to Manage Predators

Current Research

  • Urban coyotes and conflict in the Denver metro area
  • Managing intraguild predation of coyotes on black-footed ferrets
  • Landscape genetics of coyotes in the southwestern United States
  • Estimating population size and turnover rate of feral dogs
  • Landscape pattens of Mexican wolf depredation
  • Impacts of urban development on movement, behavior, resource selection, and poulation biology of black bears
  • Estimating Mexican wolf population size non-invasively 


  • Ph.D., Colorado State University, Ecology
  • M.S., University of Nevada--Reno, Biology
  • B.S., Colorado State University, Fishery and Wildlife Biology (Statistics minor)

Contact Information

  • Address: USDA/APHIS/Wildlife Services, NWRC, 4101 LaPorte Ave., Fort Collins, CO, 80521
  • Telephone: 970-266-6092
  • Fax: 970-266-6138
  • E-mail:

Recent Publications


Bonnell, M.A. and S.W. Breck. 2017. Using resident-based hazing programs to reduce human-coyote conflicts in urban environments. Human-Wildlife Interactions 11(2):146-155. doi:

Breck, S.W., S.A. Poessel, and M.A. Bonnell. 2017. Evaluating lethal and nonlethal management options for urban coyotes. Human-Wildlife Interactions 11(2):133-145. doi:

Stone, S.A., S.W. Breck. J. Timberlake, P.M. Haswell, F. Najera, B.S. Bean, and D.J. Thornhill. 2017. Adaptive use of nonlethal strategies for minimizing wolf-sheep conflict in Idaho. Journal of Mammalolgy 98(1):33-44.  doi: 10.1093/jmammal/gyw188


Blackwell, B.F., T.L. DeVault, E. Fernandez-Juricic, E.M. Gese, L. Gilbert-Norton, and S.W. Breck. 2016. No single solution: application of behavioural principles in mitigating human-wildlife conflict. Animal Behavior 120:245-254.  doi: 10.1016/j.anbehav.2016.07.013  

Bonnell, M.A., and S. Breck. 2016. Using coyote hazing at the community level to change coyote behavior and reduce human-coyote conflict in urban environments. Proceedings of the 27th Vertebrate Pest Conference 27:97-102.

Breck, S.W., S. Poessel, and M.A. Bonnell. 2016. Evaluating lethal and non-lethal management options for urban coyotes. Proceedings of the 27th Vertebrate Pest Conference 27:103-111.

Poessel, S.A., S.W. Breck, and E.M. Gese. 2016. Spatial ecology of coyotes in the Denver metropolitan area: influence of the urban matrix.Journal of Mammaolgy 97(5):1414-1427.  doi: 10.1093/jmammal/gyw090  

Piaggio, A.J., C.A. Cariappa, D.J. Straughan, M.A. Neubaum, M. Dwire, P.R. Krausman, W.B. Ballard, D.L. Bergman, and S.W. Breck. 2016. A noninvasive method to detect Mexican wolves and estimate abundance. Wildlife Society Bulletin 40(2):321-330.  doi: 10.1002/wsb.659  


Young, J.K., M. Mahe, and S. Breck. 2015. Evaluating behavioral syndromes in coyotes (Canis latrans). Journal of Ethology 33(2):137-144.  doi: 10.1007/s10164-015-0422-z  

Lewis, D.L., S. Baruch-Mordo, K.R. Wilson, S.W. Breck, J.S. Mao, and J. Broderick. 2015. Foraging ecology of black bears in urban environments: Guidance for human-bear conflict mitigation. Ecosphere 6:art141.

Johnson, H.E., S.W. Breck, S. Baruch-Mordo, D.L. Lewis, C.W. Lackey, K.R. Wilson, J. Broderick, J.S. Mao, and J.P. Beckmann. 2015. Shifting perceptions of risk and reward: Dynamic selection for human development by black bears in the western United States. Biological Conservation 187:164-172.  doi: 10.1016/j.biocon.2015.04.014

Poessel S.A., S.W. Breck, K.A. Fox, and  E.M. Gese. 2015. Anticoagulant rodenticide exposure and toxicosis in coyotes (Canis latrans) in the Denver metropolitan area.  Journal of Wildlife Diseases 51(1):265-268.  doi: 10.7589/2014-04-116.


Lewis, D.L., S.W. Breck, K.R. Wilson, and C.T. Webb. 2014. Modeling black bear population dynamics in a human-dominated stochastic environment. Ecological Modelling 294:51-58.  doi: 10.1016/j.ecolmodel.2014.08.021.

Baruch-Mordo, S., K.R. Wilson, D.L. Lewis, J. Broderick, J.S. Mao, S.W. Breck. 2014. Stochasticity in natural forage production affects use of urban areas by black bears: implications to management of human-bear conflicts. PLoS ONE 9(1): e85122. doi: 10.1371/journal.pone.0085122.


Baruch-Mordo, S., C. T. Webb, S. W. Breck, and K. R. Wilson. 2013. Use of Patch Selection Models as a Decision Support Tool to Evaluate Mitigation Strategies of Human-Wildlife Conflict. Biological Conservation 160: 263-271.  

Poessel, S.A., S.W. Breck, T.L. Teel, S. Shwiff, K.R. Crooks, and L. Angeloni. 2013. Patterns of human-coyote conflicts in the Denver metropolitan area. Journal of Wildlife Management 77:297-305. doi: 10.1002/jwmg.454


Atwood T.C. and S.W. Breck. 2012. Carnivores, Conflict, and Conservation: Defining the Landscape of Conflict. In eds Álvares FI, Guilherme EM. Carnivores: Species, Conservation, and Management. Nova Science Publishers. pp. 99-118

Breck, S., P. Clark, L. Howery, D. Johnson, B. Kluever, S. Smallidge, and A. Cibils. 2012. "A Perspective on Livestock Wolf Interactions on Western Rangelands." Rangelands 34 (5): 6-11.  

Breck, S. W., M. I. Goldstein, and S. Pyare. 2012. "Site-Occupancy Monitoring of an Ecosystem Indicator: Linking Characteristics of Riparian Vegetation to Beaver Occurrence." Western North American Naturalist 72 (4): 432-441.

Clark, L., P. J. Savarie, J. A. Shivik, S. W. Breck, and B. S. Dorr. 2012. "Efficacy, Effort, and Cost Comparisons of Trapping and Acetaminophen-Baiting for Control of Brown Treesnakes on Guam." Human-Wildlife Interactions 6 (2): 222-236.

Kluever, B. M., L. Lagos, S. W. Breck, D. L. Bergman, L. D. Howery, M. L. Sanmartin, and F. Bárcena. 2012. "Integrity and Retention of Ear-Tag Radiotransmitters in Domestic Cattle and Feral Horses." Wildlife Society Bulletin 36 (1): 189-193.  


Atwood, T. C., J. K. Young, J. P. Beckmann, S. W. Breck, J. Fike, O. E. Rhodes, and K. D. Bristow. 2011. "Modeling Connectivity of Black Bears in a Desert Sky Island Archipelago." Biological Conservation 144 (12): 2851-2862. 

Baruch-Mordo, S., S. W. Breck, K. R. Wilson, and J. Broderick. 2011. "The Carrot Or the Stick? Evaluation of Education and Enforcement as Management Tools for Human-Wildlife Conflicts." PLoS ONE 6 (1).. 

Biggins, D. E., T. M. Livieri, and S. W. Breck. 2011. "Interface between Black-Footed Ferret Research and Operational Conservation." Journal of Mammalogy 92 (4): 699-704. 

Breck, S. W., B. M. Kluever, M. Panasci, J. Oakleaf, T. Johnson, W. Ballard, L. Howery, and D. L. Bergman. 2011. "Domestic Calf Mortality and Producer Detection Rates in the Mexican Wolf Recovery Area: Implications for Livestock Management and Carnivore Compensation Schemes." Biological Conservation 144 (2): 930-936. 

Cariappa, C. A., J. K. Oakleaf, W. B. Ballard, and S. W. Breck. 2011. "A Reappraisal of the Evidence for Regulation of Wolf Populations." Journal of Wildlife Management 75 (3): 726-730.  

Panasci, M., W. B. Ballard, S. Breck, D. Rodriguez, L. D. Densmore III, D. B. Wester, and R. J. Baker. 2011. "Evaluation of Fecal DNA Preservation Techniques and Effects of Sample Age and Diet on Genotyping Success." Journal of Wildlife Management 75 (7): 1616-1624. 

Poessel, S. A., S. W. Breck, D. E. Biggins, T. M. Livieri, K. R. Crooks, and L. Angeloni. 2011. "Landscape Features Influence Postrelease Predation on Endangered Black-Footed Ferrets." Journal of Mammalogy 92 (4): 732-741. 


Lance, N. J., S. W. Breck, C. Sime, P. Callahan, and J. A. Shivik. 2010. "Biological, Technical, and Social Aspects of Applying Electrified Fladry for Livestock Protection from Wolves (Canis Lupus)." Wildlife Research 37 (8): 708-714. 

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