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    Getting to Know Connecticut’s Black Bears


Black bears (Ursus americanus) have become an unmistakable presence in Connecticut. As their population has grown, these adaptable omnivores have expanded their range to include both rural and suburban areas of the state, bringing them into close proximity with people. Black bears’ increasingly conspicuous presence has raised many questions about their population. Exactly how many bears call Connecticut home is one of the most important. For the past decade, the Department of Energy and Environmental Protection (DEEP) Wildlife Division has been using radio-telemetry and GPS collars to monitor the movements, survival and reproduction of a small group of bears. Now, the University of Connecticut is collaborating with DEEP to create the first scientifically-based estimate of the number of black bears in Connecticut. This research, which was initiated in the summer of 2012, uses genetic methods to identify individual bears from the DNA contained in their hair. Using new quantitative techniques that expand on the traditional mark-recapture population estimates, these DNA fingerprints are used to estimate local abundance and density.

So how do we gather enough hair to figure out how many black bears reside in Connecticut? Amazingly, the bears donate it themselves. Small ‘hair corrals’ are used to passively collect bear hairs in a non-invasive manner. These consist of barbed wire strands stretched between trees to form an enclosure. When bears cross the low strung wire to investigate interesting scents placed in the center of these corrals, hair is snagged on the barbs. The simple genius of this method lies in the bounty of data we can collect without capturing the animals.

In addition to providing the ability to uniquely identify different bears, genetic data can be used to infer relationships among these individuals. Combined with the locations at which individuals are encountered, we can use this information to quantify the spacing of family groups and the distances that young bears disperse.

Want to learn more about the results of this project?

1- Check out the 4 minute video of Tracy being interviewed by CT NBC TV news.
2- Listen to the webinar titled "The Bears are Back: Research, Results and Ruminations about Connecticut's Bears" (recorded May 5,2016).
3- Visit the interactive story map created by Mike Evans and Cary Chadwick (UConn CLEAR).  Make sure you type in your home address on the orange map of housing density and red map of bear density.  

Publications resulting from this research:

Evans, M.J., J.E. Hawley, P.W. Rego, and T.A.G. Rittenhouse. 2018. Individual movement decisions indicate how a large carnivore inhabits developed landscapes. Oecologia. 2018:1-13.

Evans, M.J., and T.A.G. Rittenhouse. 2018. Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras.  Journal of Animal Ecology. 55:2565-2574.

Evans, M.J., T.A.G. Rittenhouse, J.E. Hawley, P. Rego, and L. Eggert. 2018. Spatial genetic patterns indicate mechanism and consequences of large carnivore cohabitation within development. Ecology and Evolution. 8:4815-4829.

Evans, M.J., T.A.G. Rittenhouse, J.E. Hawley, and P.W. Rego. 2017. Black bear recolonization patterns on human-dominated landscapes vary based on housing: New insights from spatially explicit density models. Landscape and Urban Planning 162:13-24.
Wildlife and Fisheries Conservation Center
Department of Natural Resources and the Environment
University of Connecticut
1376 Storrs Road, Unit 4087