Bears in the neighborhood
As a department head at Colorado State University, biologist Ken Wilson doesn’t get out into the field as much as he might like.
But he was able to participate some with the school in its role in a five-year bear study in the Aspen area, which left him with some indelible memories about an animal he admires a lot. Wilson, head of CSU’s Department of Fish, Wildlife and Conservation Biology, treasured experiences such as working with a hibernating mother with newborn cubs in a den on Aspen Mountain.
“It’s wonderful, seeing an animal up close that’s that beautiful,” he said.
When it comes to getting close-up views of bears, however, Wilson’s hardly alone among Coloradans. The animals frequently pay visits to some mountain towns, and the outcomes aren’t always good, particularly for the bears. Some end up having to be destroyed under a state policy applying to problem bears that return to cause more problems after being relocated out of town.
The recently concluded Aspen study focused on issues surrounding bears in urban areas, and five years of new research on the subject is beginning in the Durango area. The hope is to help wildlife managers and ultimately the public understand how to minimize problems and enable bears and people to continue to coexist in states such as Colorado, where Wilson and so many other residents appreciate their presence.
“They’re a tremendously wonderful animal, and we’re fortunate to have them here in Colorado,” he said.
Dealing with urban bear problems has proven to be a considerable challenge in the state, however. Wilson’s student, Sharon Baruch-Mordo, who is pursuing a doctorate degree, has been the lead author on papers about findings of the Aspen study, which included as partners Colorado Parks and Wildlife and the federal National Wildlife Research Center, and received other financial support.
The costs of conflict
Baruch-Mordo reports that in 2009 the state’s wildlife agency spent 5,000 hours and $200,000 responding to human-bear conflicts in the Aspen region alone.
In another problem year, 2007, wildlife officials moved or killed 35 bears in Aspen and surrounding areas because of conflicts, Baruch-Mordo wrote.
Those conflicts largely result from bears being drawn to urban-area trash and other food sources, which the recent research suggests particularly corresponds to summer seasons of poor production of natural food sources such as serviceberries and gambel oak acorns. Such production can be affected by factors such as drought or late frosts.
Part of the Aspen-region study involved fitting bears with global-positioning-system collars from 2005 to 2009. The collars captured bear locations at 15- or 30-minute intervals. Researchers then could use radio tracking to find the bears at times such as hibernation and retrieve the collars.
One of the most notable findings turned out to be that Aspen-area bears that spent a lot of time eating urban food during a given year didn’t seem to make a multiyear habit of it. If natural food production improved the next year, they tended to spend much of their time in the backcountry instead. Baruch-Mordo reports that in 2008, a good year for natural food growth, five of six study bears spent little time in town limits compared to 2007, a poor natural food year.
The habitat shifts even occur within a season, such as when natural food sources ripen. And other factors also appeared to play roles, as in the case of a female bear that largely avoided Aspen during a good natural food year when she had cubs, but spent more of a mix of time in and out of town during another good natural food year when she was on her own.
John Broderick, who is terrestrial programs manager for Parks and Wildlife and was involved in the study, said the findings run counter to research in the Lake Tahoe region suggesting that urban bears there remain urban bears once they habituate to urban food sources. A reason may be that the Aspen backcountry is thought to offer better bear habitat than natural habitat around Lake Tahoe.
Said Wilson, “Here in Aspen, it really shows us bears want to be bears, and they really don’t want to interact with humans if they don’t have to.”
The human dimension
Much of the effort to keep bears out of Colorado communities has focused on getting residents not to leave trash, dog food, barbecue grills and other attractions outside, and to take other steps such as closing doors and windows to keep bears out of homes. The Aspen research took a closer look at this effort, becoming as much a study of human behavior as bear behavior. Pitkin County and Aspen have ordinances dictating human activities to address the bear problem. The study found that humans respond much better to enforcement rather than education in following rules regarding bears.
The study explored the results of a two-week educational effort by Bear Aware volunteers in some neighborhoods. Researchers who surreptitiously recorded observations in unmarked vehicles found no difference in the availability of trash to bears or the use of bear-resistant containers between areas targeted for education and control groups.
A similar study in New York found an education campaign there also failed to result in humans reducing bear attractions.
However, the Aspen study found that when Aspen police issued written warnings to Aspen Dumpster operators for violating bear ordinances, there was a 40 percent drop in the probability of noncompliance by those operators.
Broderick said that doesn’t mean education shouldn’t be abandoned, but it’s important to understand the effectiveness of various measures, including enforcement.
“You’ve got to have several tools in your toolbox. You can’t just count on one of them,” he said.
In Aspen, residents are required to use bear-resistant containers. Unless they have sturdier, metal, bear-proof containers, they must not put them out until the morning of collection, and they must take them back inside by 6 p.m.
Aspen Police Department spokeswoman Blair Weyer said police try to educate first and tend to issue tickets in the case of repeat offenders.
Wilson said human nature being what it is, it’s no surprise the role that enforcement would play in the case of bear ordinances, just as motorists obey traffic laws more after they’re ticketed for violations. He wouldn’t mind seeing more enforcement, but also lamented, “All we have to do is take care of our trash.”
Eric Johnson, assistant manager of Alpine Ace Hardware in Aspen, said a good number of the bear-resistant trash containers his store sells are to people who have received warnings or tickets.
“It’s just like anything else. Some people procrastinate, and some people don’t,” he said.
Sink or source?
Meanwhile, researchers wonder what the ultimate consequences are for bears when urban food is available and draws them to communities. Do bear numbers ultimately grow because of the availability of that food, or suffer because of bears that have to be put down, or die for other reasons such as being hit by cars?
The Durango research being launched by Parks and Wildlife is looking into this question of whether urban areas serve as sinks or sources for bear populations. It will seek to learn about cub production levels, adult and cub survival rates and other population data for bears using urban areas, and the results will be compared with bears that live only in the wildlands in that region.
In other research back in Aspen, another graduate student is doing capture and analysis of hair snare samples in the area. The samples can be traced to specific bears. After wildlife authorities doubled hunting licenses in the Aspen area last year, the bear harvest there doubled. Authorities want to look at whether bears being harvested each year are the same ones showing up in town, meaning hunting is playing an effective role in controlling bear numbers around towns.
State Rep. J. Paul Brown, R-Ignacio, has proposed legislation that would loosen a 1992 voter-approved requirement that resulted in bears being hunted only in the fall. That limitation sprung from objections to hunting of bears during the spring, when cubs are young. Brown said he’s not necessarily proposing reviving spring bear hunts, but summer hunts might be warranted.
Brown said the 1992 measure ties wildlife officials’ hands. However, he said he agreed to hold off on pursuing his legislation until wildlife officials get results from their further research.
Still, he said, “We’re having more and more human-bear conflicts and more bites and more actual attacks, and this is concerning to me.”
Those attacks include recent ones in the backcountry outside Aspen. Campers were bitten through their tents, in one case seriously injuring a man.
Wilson said while such incidents certainly are serious, they also are rare. Numerous people visit Colorado’s backcountry each year without being attacked by bears, he said.
Likewise, bears coexist with humans in urban areas surprisingly well, Wilson said. He said the Aspen research showed that even in years of good natural food production, bears still frequently crisscrossed urban areas despite tending to spend more time out of town. Yet people had the impression there were no bears around.
“I think a fascinating thing for me is that bears are for the most part really good citizens … whether a good or bad (natural food) year,” he said.