Moose collaring in state is over, but not research
St. Paul — Gov. Mark Dayton may have ended the practice of collaring moose in the state with his April 28 executive order, but researchers’ attempts to get to the bottom of what’s killing the iconic animals continue.
At the time of the order, the DNR had studies – both of which began in 2013 and used radio collars – looking at adult and calf moose mortality.
Calf collaring set to begin in May was scuttled, but researchers are using alternative methods in an attempt to keep the information flowing. About 100 adult moose already had collars on them, so researchers will learn from them until the collars go off the air.
The original design of the adult study was for three years and officials wanted to keep 100 animals collared. Researchers had extra money from the Environment and Natural Resources Trust Fund and were considering a fourth year of collaring next year. That, of course, won’t happen now.
Of the 100 or so adult moose with collars, 60 of them also have mortality implant transmitters, which, among other things, record internal temperature and heart activity. There’s a gap in the knowledge of moose physiology in that area, and the DNR’s project is attracting a lot of interest from other researchers, said Michelle Carstensen, DNR wildlife health program supervisor.
“If we identify, for example, that there’s points in time where moose have excessive heat and we find they go to certain areas for refuge, does our landscape offer enough of that?” she said.
During the first year of the adult moose study, about 19 percent of the collared animals died. The second year, about 12 percent of the collared animals died. Officials say normal rates of mortality are in the 8 percent to 12 percent range on an annual basis.
So far this year, four of the collared adults have died. That’s comparable to the number at the same time last year.
“The hard winters have been good for them,” Carstensen said. “Right now, the mortalities have been low and survival is going to be up again this year. But I think that will change next year.”
That’s because the mild winter makes it more likely that winter tick abundance will increase.
The most recent collared moose that died apparently broke through the ice on a creek while being chased by wolves. The wolves didn’t break through, and killed the animal. The other was a 15-year-old female moose that died. Researchers got to her within 20 hours after her death, but the majority of her remains already had been scavenged.
So far, 36 collared moose have died during the study. It takes animals dying, of course, for researchers to learn about what’s killing them.
“It depends on what happens this year, but I would predict we won’t do any data analysis until after the fourth year,” Carstensen said. “Right now, the causes of mortality are equally split between wolves and health-related causes.”
She notes, though, that wolves are taking moose of nearly every age, and that “wolves shouldn’t be preying on those prime-age animals.” In addition, some animals are dying from health effects at younger ages.
“We are seeing things affecting this population at all ages,” Carstensen said.