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A team of researchers from the Minnesota Department of Natural Resources, the Fond du Lac Band of Lake Superior Chippewa, the Minnesota Zoo and other groups are trying to figure out why.
Scientists said the animals are dying of “tipover disease,” meaning they just weaken and fall to the ground where they are finished off by wolves and other predators.
The cause might be parasites the moose have picked up from a skyrocketing deer population, or it might be a complication from warming winters, or some complex combination of things.
The answers to their questions could help the scientists shed light on broader changes in the North Woods, where the moose is an iconic part of the landscape.
“When you think of northern Minnesota, you think of the North Shore, the Boundary Waters, wolves, loons and moose,” Mike Schrage, wildlife biologist for the Fond du Lac Band told the Star Tribune of Minneapolis. “They’re part of our identity.”
The scientists have been flying over northern Minnesota this month, shooting tranquilizer darts down into the moose. They take samples of blood and tissue for testing then put collars on the animals so the scientists can track their movements.
This year, the collars will carry a new device — a thermometer to record the temperature in the moose’s surroundings.
Schrage and DNR wildlife researcher Mark Lenarz said that may help determine whether moose are finding places in the woods cool enough for the animals to stay healthy. If they can prove that theory, that could lead to forestry and wildlife management efforts to protect and enhance such areas.
The average midwinter temperatures in northwest Minnesota increased about 11 degrees from 1961 to 2001, a huge change in climactic terms. Scientists are researching temperature trends to the northeast.
Schrage said he believes mild winters and longer growing seasons are a threat to the northeast moose, but they don’t explain everything.
“It’s complicated in between a warm climate and a dead moose,” he said. “I don’t think I’m ever going to walk up to a dead moose and say, ’Oh, it died of heat stress.’ There’s a lot that happens in between.”
