Citing his deep concerns with the growing number of moose that have died soon after being captured and radio-collared, Minnesota Governor Mark Dayton suspended all capture/collaring efforts by DNR wildlife research scientists “immediately and indefinitely.” It is getting harder and harder to see moose like this cow and calf photographed in a Gunflint Trail pond. The DNR reports that Minnesota’s moose herd has fallen from 8,840 in 2006 to an estimated 3,450 in 2015.
On April 28, Minnesota Governor Mark Dayton put the kibosh on the Department of Natural Resources (DNR) plans to capture and collar any more moose this year or for any time in the foreseeable future.
“I respect that DNR researchers are trying to understand why our moose population is declining,” said Governor Dayton. “However, their methods of collaring are causing too many of the moose deaths they seek to prevent. Thus, I will not authorize those collaring practices to continue in Minnesota.”
Dayton’s decision will end DNR researcher Glen DelGiudice’s plans to collar 50 newborn calves this spring and also falls on the heels of the adult capture/collar stopped earlier this year after five moose died soon after being captured.
Michelle Carstensen, the DNR Wildlife Health Program supervisor, said the adult study was ended after 32 of a planned 36 moose were collared. Carstensen said four of the five suffered “capture myopathy,” a disorder of the muscles that occurs soon after capture.
“The fifth moose had a massive seizure,” Carstensen said. “We found a lesion on her adrenal gland that could have produced stress hormones and caused her to die. That’s just a guess. But it might have had something to do with her seizure.”
Every night the crew would assess what had happened during the capture/ collar process, said Carstensen, and make modifications to prevent any more deaths, but they kept recurring.
“We decided not to go out the final day. We had 27 survive and it wasn’t worth the risk,” said Carstensen. “We have been capturing and collaring moose for many, many years and have never had results like this.
“We didn’t do anything differently than we have in the past. We hired Dr. Terry Kreeger once again to help us determine the dose for the tranquilizing drugs we used. He literally wrote the book on animal captures. At the start we used the same dosages as last year. We try to assess how the moose are doing in the process and make changes from there. The goal is to keep the dosage low enough so the animal gets up within 10 minutes. Most got up in four minutes.
“The ones with “capture myopathy” would wake up and look at us and try to get up but they couldn’t get their back ends up. We would wait for them to get up but after awhile it was apparent they wouldn’t be able to stand so we put them down.
“After the first one died we changed the tranquilizer dose for the next day. The first seven we captured were fine but the eighth one suffered the same condition.
“We did this every day and every day we would lose one. It was very frustrating, very sad. It was also unprecedented. We typically lose two to three percent of moose we capture/ collar. This year it was 20 percent.
“Early findings from the autopsies show that two of the moose had mild forms of encephalitis and one other had a lesion on its adrenal gland. We can’t say for sure that these conditions had any bearing on their dying. We just don’t know yet.”
As far as capturing moose calves, DelGiudice’s team was supposed to start its third year of capture/ collar this May. Last year 25 moose calves were collared 36 – 48 hours after they were born. Soon after 19 calves were either abandoned by their mothers or rescued by researchers (who took them mostly to zoos) or they slipped their collars and couldn’t be tracked.
By mid-August the six left in the study were eaten by wolves or bears.
During the first year nine calves were abandoned and necropsies found they had starved to death. Wolves also took a lot of the calves and researchers found that more than 70 percent of them didn’t make it through their first winter.
All told, cows abandoned 16 of the 74 newborns that were collared, something Governor Dayton—and much of the general public—found unacceptable.
As for Carstensen, she said the adult moose study would be ongoing because there are still 99 of the 168 GPS collared moose left for researchers to follow.
“The collars stay on for four to five years so we should get a lot of data. We will stay on task and try to get answers to what is killing Minnesota’s moose. I think it won’t take five years to get the answers. I hope in the next two years or so we can come out and say we know what is killing the moose and hopefully have a plan to help them, if that is possible.”
While the DNR has long collared North America’s largest herbivore, it wasn’t until 2013 that GPS tracking collars and mortality implants were used to help gather real-time data.
The implants should give researchers an idea of whether or not the moose are overheating in the summer, said Carstensen.
“We have been wondering if moose have been getting too hot in the summer and that is causing them problems,” said Carstensen. “Maybe they have been, but maybe not. We really don’t know. Now we will have some data that will help us determine if this is true. If it is true, we can make plans to help create a better habitat for moose. Maybe we can help that way.”
So far scientists know that winter ticks, brain worm, disease, habitat, and predators all take their toll on the moose population. But why the moose are dying off at such an alarming rate is a mystery that must be solved.
In 2006 the DNR estimated the state’s moose population at 8,870. By 2015 the DNR put the population at 3,450, a decline of 60 percent.
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