Minnesota moose numbers low but stable
DULUTH—Northeastern Minnesota's moose population dropped some during the past year, but it appears to have leveled off after the big declines of a decade ago.
The Minnesota Department of Natural Resources reported Thursday that its annual winter moose estimate came in at 3,030 moose, an 18 percent drop compared to 3,710 moose in 2017. The agency said the decline was statistically insignificant.
The state conducts an aerial survey each winter, flying helicopters over predetermined quadrants to count moose. Biologists enter those numbers into a formula to determine the overall population across the 6,000 square miles of moose range in Cook, Lake and St. Louis counties.
Statistically, the DNR is 90 percent certain that the population is somewhere between 2,320 and 4,140 moose.
"While the population appears stable, low numbers of moose are still a major concern for the DNR," said Tom Landwehr, DNR commissioner, in a statement. "We continue to pursue the best science, research and management tools available to us to help Minnesota's moose."
Northeastern Minnesota held nearly 9,000 moose as recently as 2006. Their numbers began to plummet rapidly after that and are now down two-thirds. But most of the decline was in the first few years, with the last seven surveys fairly stable.
Scientists have been studying myriad possible causes for the decline, and they have found a complicated web of factors. More years with warmer temperatures and less snow may be pushing other issues, such as allowing deer numbers to increase in moose range. Deer carry a parasitic brainworm that is extremely fatal to moose, although harmless to deer.
Warmer weather also stresses moose, so they eat less and have less fat to survive winter. Warmer winters with less snow also allow more parasites, such as winter ticks, to thrive; some moose can carry thousands of blood-sucking ticks.
Wolves also are a major factor, especially once the moose population began to drop. Wolves are now holding down calf numbers, thwarting any recovery of the overall population. Cow moose are getting pregnant and having calves, DNR research found, but very few calves are living to their first birthday. Research shows wolves are killing about two-thirds of all calves that die in their first year compared to about one-third of the adults that die annually.
Aging forests with less moose habitat also may be an issue. Scientists have noted that some of the few areas with increasing moose numbers in recent years are where big fires have occured in the past decade, clearing the way for a younger forest that has the type of food on which moose thrive.
Despite the lack of any population increase, the stable numbers are better than rapid declines, researchers said.
"The stability of moose numbers in recent years provides a reason for some optimism ... we're not facing a significant decline," said Glenn DelGiudice, the DNR's moose research leader. "But this year's results would be more palatable had they reflected the beginning of a turnaround in the population trend."
Minnesota once had a large population of moose in the northwestern reaches of the state, but that population dwindled to nearly zero by the late 1990s.
"The good news is that the northeast population isn't stair-stepping down to nothing like the northwest did, at least for now," DelGiudice said.
DelGiudice said research efforts during the past several years have helped spur some action to try to bolster moose numbers, including ending the state's limited moose hunt, managing deer numbers at lower densities in moose range to slow the spread of brainworm, and bolstering habitat through logging projects.
This year's survey involved flying over 52 of the 436 moose survey plots distributed across Northeastern Minnesota's moose range from Jan. 3 to Jan. 13. The Fond du Lac Band of Lake Superior Chippewa and 1854 Treaty Authority contributed funding and provided personnel for the annual moose survey.