Biologists seeking bear dens


Roscommon, Mich. — Michigan Department of Natural Resources biologists want the public’s help to locate denned bears the department uses to collect data, rehome orphaned cubs and train staff on handling wildlife.

DNR officials started tracking bear dens in 2005 after acquiring orphaned bear cubs who were abandoned by their mother at a logging site. With no dens located, the department eventually turned the cubs over to an Upper Peninsula wildlife farm, biologist Mark Boersen told Michigan Outdoor News.

“So we decided at that time to keep a small number of female bears collared over time,” he said.

Sows with cubs are protected during hunting season, but nearly each year bear cubs are orphaned when their mothers are killed in car collisions or other tragedies Boersen said, and DNR officials place the young bears with sows denned for the winter.

“You can give orphaned cubs to a female with cubs of her own and quite often it’s successful,” he said. “This year I actually had two different litters of cubs I gave to bears who we had radio collars on and it appears it was successful.”

Biologists use tips from the public to track down sows in their den that are tranquilized and removed along with her cubs for an exam. Biologists take a tooth to determine the bear’s age and to collect a DNA sample, and return the animals to their den – the sow with a radio collar and ear tag.

Biologists then revisit denned bears each year to adjust the radio collars, and to record valuable biological information like weights, litter numbers and other data used to gauge the health of the state’s bears. Currently, DNR officials are tracking five collared sows, with one young female added this fall.

“If we were seeing (sows) with only one cub or two cubs … we would know we might have a problem with our bear population,” Boersen said. “What we have been seeing is (sows) with three or four cubs. They are continuing to be very productive into their teens and early 20s and that tells us they are doing really well.”

Boersen said the annual den visits are also opportunities for biologists to get hands-on experience with Michigan bears.

“We use it as a training tool to train our staff on the proper way to manage wild animals with these tranquilizer drugs,” he said. “We keep people who are qualified trained to handle the drugs.”

Hunters and other outdoor enthusiasts can contribute to the DNR’s bear research by recording bear den sites they encounter with a GPS unit, and forwarding the coordinates to Boersen’s email:

“A lot of times you will see a whole dug out of the ground and look in and you’ll see the bear in there,” Boersen said, adding that it’s illegal to disturb or harm the animal in its den.

Officials work to monitor numerous sows from across the state, he said, though currently most are in the northern Lower Peninsula.

“They are literally all over the northern Lower, from Manistee County all the way up to Cheboygan … Roscommon counties,” he said. “I don’t get much south of Cadillac.”

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