Colorado State University Study Shows Bears in Aspen Don’t Necessarily Have Preference for Trash

Turns out that trash isn’t one of the bear necessities in the Aspen area, according to a new study by Colorado State University. The study was conducted by ecology doctoral candidate Sharon Baruch-Mordo and suggests that bears actually prefer to eat wild berries and oak acorns.

The collaborative study includes researchers and managers with the U.S. Department of Agriculture’s National Wildlife Research Center and the Colorado Division of Wildlife. As part of an ongoing study to better understand the urban ecology of bears, the team has tracked the movement of about 50 American black bears over the past five years in and around the city of Aspen in Pitkin County, Colo. This area has a recent history of human-bear conflicts.

Researchers set out to discern when and why bears ventured into town. Beyond tracking where and when the bruins roamed, the team also experimented with public education techniques and efforts to keep human trash securely locked up and out of reach of bear paws.

“What we found is that bears are just being bears in urban environments. When natural food sources were bountiful, bears rarely came into town,” said co-principal investigator Ken Wilson, a professor in the Department of Fish, Wildlife, and Conservation Biology at CSU. “When natural food sources were lean, bears were creative and resourceful enough to track down more easily attainable human food. Perhaps more interesting, we found that bears did not become addicted to trash and, in fact, the patterns of seeking human food reversed when more natural food was available in subsequent years.”

The findings suggest that Aspen’s problems with human-bear conflict can be eased, but it will take people changing their behavior in regards to securing garbage to make a significant impact.

“An essential key to reduce the number of bear-related conflicts for the residents of Aspen and surrounding areas is to make sure garbage is secure at all times. Over the course of our study, we have seen that when natural food sources are poor, as they were in 2007 and 2009, bears will venture into Aspen and during those years we saw high incidents of human-bear conflicts,” Wilson said.

As part of the study, researchers evaluated the effectiveness of education and enforcement in reducing conflict between humans and black bears in Aspen by directly measuring changes in human behavior.

“We experimentally tested on-site education, a neighborhood-wide Bear Aware campaign, and two levels of elevated law enforcement treatments; these are management techniques frequently used or promoted by wildlife agencies, municipalities and conservation organizations to change human behavior and reduce human-bear conflicts,” said Stewart Breck, research wildlife biologist and co-principal investigator with USDA.

Results suggest that the education methods evaluated were ineffective in changing human behavior in terms of properly securing trash. However, proactive law enforcement techniques were somewhat effective in getting residents to secure their trash.

“Over the past five years, we learned a lot about bears and people and how they interact in the urban environment. There haven’t been many long-term studies of black bears in urban settings, and we need to understand whether similar results are found in other regions of Colorado,” said Wilson. “We also need to continue to develop and evaluate education and enforcement efforts to better affect change in human behavior.”

“From a wildlife management perspective, a key research question is how removal of bears in severe conflict years affects the bear population. We hope that our study results inform local municipalities, wildlife agencies and residents in how to better coexist with bears. This study has also resulted in an extremely successful collaboration for the partners: USDA, CDOW and CSU. Ultimately, our aim is to help reduce human-bear conflicts in mountain communities like Aspen and urban areas in general,” said John Broderick, Terrestrial Programs Leader and co-principal investigator with the CDOW.