Experts conduct bear den surveys in area
By BILL ZIEGLER
For The Daily News
CRYSTAL FALLS – A group of graduate students from Mississippi State University and the Michigan Department of Natural Resources Wildlife Division are conducting a comprehensive study in the Upper Peninsula to determine how various predators and winter conditions impact deer fawn survival.
The initial part of the study was completed in the Menominee area of Delta County. The researchers monitored predator contributions to fawn mortality in low snow conditions for three years in Menominee County.
Now, the same research study is being conducted in the moderate snow/winter conditions of eastern Iron County and part of northern Dickinson County. If the study goes as planned, the same will take place in the deep snow conditions of the northern Upper Peninsula (such as Baraga and Ontonagon counties) after the study portion in Iron County is completed.
The overall study is led by Dr. Jerrold Belant of Mississippi State University and Dr. Dean Beyer of the Michigan DNR Wildlife Division. It should be noted that Dr. Belant formerly conducted bear research in the Pictured Rocks National Lakeshore.
This research project was funded by Safari Club International, Michigan DNR Wildlife Division, and the Delta County Chapter of U.P. Whitetails Association.
The researchers are based in Crystal Falls for three years. Don’t let the Mississippi State University affiliation throw you; most of the researchers working on this study are from the Midwest including Michigan and Indiana. They are working throughout each year on different aspects of the study.
In late February, the research team conducted their bear den surveys and I was invited along.
Initially, the bears are trapped during their active summer periods and radio collared. The collars are used to follow the bears’ activities throughout the year to help determine their feeding habits, habitat use, and contribution to deer fawn mortality.
The radio or GPS radio collars need to be replaced after a year to replace their batteries. The collar is used to locate the winter bear den. Much of the monitoring of collared predators is done with researchers in DNR aircraft.
The researchers confirm the den site and mark the site electronically and with tree ribbon in December just in case the collar fails. The research team returned in late February to recollar the bear and take a number of measurements. The February survey period allows the research team to determine if female bears have given birth to cubs.
The team travelled by snowmobile and pulled sleds several miles east of the Deer River to a remote part of eastern Iron County.
We snowshoed into a recent clear cut with small aspen. The bear den was excavated by the female bear under a leaning high stump.
The entrance to the den was completely covered with snow with only a small air vent that melted with the body heat of the mother bear and the cubs.
Tyler Petroelji, head research assistant, and Dean Byer, DNR research biologist, dug out the den entry and administered the anesthetic to the adult female bear with the use of a “jab stick.”
Petroelji had to go down the fairly deep den hole head-first to extract the mother bear and cubs. When he was ready, the team pulled him out with a strap around his leg.
It took several members of the team to pull the female bear out and she was then placed on an old sleeping bag and covered with another sleeping bag.
Next, Petroelji went back head first into the den hole and each time was pulled out with another cub.
Petroelji removed a total of three cubs in this den. The cubs were immediately handed off to other team members who placed the squirming little cubs inside their jackets to keep them warm.
Keeping the cubs warm in their jackets was a very popular job with the extra members of the research team.
Petroelji said he could tell there were cubs in the den before digging out the entrance because they make a sort of purring noise when they are nursing on their mother.
After seeing how subtle the bear den entrance was, DNR forester Ed Rice who was accompanying the research team for the day, wondered out loud “how many times has he walked or snowshoed by a bear den and didn’t even know it.”
Petroelji stated that it has been quite common for them to find excavated dens or dens under tilting stumps or root wads like this one in the newer aspen regeneration.
He went on to say that in Menominee and Delta counties study area, this type of habitat was limited and it was more common to find bear dens near cedar swamp type habitat.
The research team worked on taking measurements and condition factors as fast as possible from the mother bear and her cubs.
The cubs weighed in at about 2.5 pounds each and their sex was noted. They were given back to other team members as soon as possible to keep them warm in their jackets.
Several local school children from Ed Rice’s family had an excellent field trip and were able to witness the entire process at close range. The children all got to take a turn keeping the bear cubs warm in their jackets.
The big smiles on there faces showed they were having a special day on this field trip in the woods. In some cases team members were working on the adult female at both end of her body at the same time to hasten the process.
Some of the tests and assessments that were completed include: blood samples, body mass index, weight, skull and body measurements, examination of a past wound, size and condition of teeth.
This female bear weighed 153 pounds. It was quite a process for the team to lift her off the ground with a small log, tarp and scale while standing in deep snow. Petroelji said the largest bear they have handled in this way to date was 265 pounds.
When the process was completed, the female bear was placed very carefully back in her den. It took a little longer to get her immobilized body situated so the babies would have good access to continue nursing.
Then the cubs were put back in the den on the female’s belly. The last step was to block off the entrance hole with a seal of balsam boughs to keep snow from getting in on the mother bear and cubs.
The idea was to have the female bear come out of the influence of the anesthetic without anyone being around to stress her. Petroelji stated the team currently has 12 bears collared with seven females and five males.
In addition to collared bears, the team also plans to trap and collar more wolves, coyotes, and bobcats.
The collars on these smaller animals drop off the animals each year so more have to be captured and collared.
Last year they had four wolves, five coyotes, and two bobcats. The researchers also have 30 doe deer vaginally implanted with transmitters.
These transmitters provide signals when the fawn is born and its location. The research team monitors those tags closely to locate the site of a fawn birth.
Once a new-born fawn is located they can then be collared so if they are preyed upon the team will know.
When the fawns are born the team members are essentially on call to investigate any area where a fawn mortality may have occurred as soon as they can reach the site. When a predator kills and eats one of the fawns the researchers need to investigate as soon as possible to try to determine the probable species of predator that killed the fawn.
In addition to trapping and collaring predator and prey animals the investigators are conducting several other survey methods. Wolf and coyote howling surveys are being conducted. Numerous trail cameras are deployed in across the study area on game trails, and a predator hair traps are also deployed to attempt to get indirect indicators of predator populations.
At the end of the study, DNR wildlife managers and researchers should have a much better idea of what each species of predator contributes to fawn mortality.
The research is also designed to make those determinations within the limiting factor of winter conditions from low snow to high snow zones. With all the data being collected it is hoped that a better understanding can be gained on predator density and possibly hunter exploitation rates on species like bear.