Northeastern Minnesota is home to the last stronghold of moose in the state. Sadly, the region's population of this animal has been in decline since 2006. That year an estimated 8,800 moose still roamed across Lake, Cook, and St. Louis counties. Hunting for moose ended in 2012, and the latest estimate places the region's moose population at 3,450 animals. But the "good old days" for moose don't stretch as far back as many Minnesotans might assume. History shows the distribution and abundance of moose and other members of the deer family have undergone dramatic shifts in this corner of the state since European settlement.
Until the late 1800s, woodland caribou were the predominant deer species in much of the current core of Minnesota's moose range. But caribou numbers decreased rapidly as the mature conifer forests were logged. By the 1920s caribou had completely vanished from northeastern Minnesota due to loss of habitat and unregulated killing. In contrast, moose managed to flourish in the early 1900s as aspen, birch, and other broad-leaved browse proliferated. Despite the favorable moose habitat that followed the ax and saw, this moose renaissance was short-lived due to poaching, poorly regulated hunting, and disease.
By 1922 as few as 2,500 moose remained in Minnesota, and the state officially closed all moose hunting. That same year zoologist Thaddeus Surber visited Cook County to investigate. Eighteen years later, Surber provided an account of his trip in the inaugural Oct. 1940 issue of the Volunteer. "The history of moose in this region is interesting," wrote Surber regarding a conversation he had during his 1922 visit with a man who had resided near Lutsen since 1892. "Mr. C.A.A. Nelson … informs us that, with the coming of the lumberman and prospector the caribou moved northward and finally disappeared, and moose began to appear in large numbers and were very abundant for several years; but, at one time about ten years ago, they too left in great numbers." Surber speculates that human intrusion into the domain of moose, which he describes as "preeminently a beast of the wild," was the main reason for the moose's decline. He concludes his retrospective with little optimism: "The wisdom of a long-closed season such as we have had is of very doubtful benefit to an animal which is ours today, Canada's tomorrow."
In the Nov.–Dec. 1949 issue of the Volunteer, Walter Breckenridge, director of the Minnesota Museum of Natural History (now the Bell Museum), reported, "Little, if any, change in the state's moose population has occurred in the last decade or so." His article, "A Century of Wildlife," laments that poaching, disease, deer hunters' mistakes, and some wolf predation "… will probably continue to prevent this animal's increase, and the prospects of renewed moose hunting in the state are very poor."
At the time, Breckenridge and Surber were unaware that white-tailed deer were responsible for a mysterious disease afflicting moose that was first documented in 1912. Prior to the influx of loggers, settlers, and miners, deer had been rare north and east of a line from Duluth to Lake of the Woods. But the post-logging habitat was ideal for both moose and whitetails. And as deer became more common, so did reports of moose circling aimlessly, unafraid of humans, sometimes colliding with trees, and dying for no apparent reason. A 1932 Minneapolis Journal article reported, "The disease loose among Minnesota's [moose] herd is an affliction peculiar to Minnesota alone. Increasing in its intensity, it took a toll of 30 moose in the past year. … The nature of the disease … striking down the animals is not yet known."
This moose malady would long puzzle researchers. While studying moose disease in the 1930s, Robert Fenstermacher, a veterinary pathologist from the University of Minnesota, discovered small, hairlike worms in the brains of dead moose, according to a Nov.–Dec. 1983 Volunteer story titled "Moose Disease: Fifty-year Mystery." Fenstermacher was unable to link the worms to moose disease, but Roy Anderson, a biologist with the Ontario Research Foundation, did make the connection in the 1960s after unraveling the worm's complicated life cycle. At a 1963 meeting of deer biologists from Great Lakes states, Anderson reported Parelaphostrongylus tenuis was the culprit and that white-tailed deer were the carrier of this parasitic nematode commonly called brainworm.
Divergent trends in moose and deer populations seemed to corroborate Anderson's findings. In the late 1950s the state's moose population, which may have dipped as low as 500 animals, began to grow significantly, expanding from northeastern Minnesota to the prairie edge of the northwest. The trend continued throughout the 1960s. By 1967 more than 7,000 moose roamed wilderness areas in northeastern and northwestern Minnesota, according to "A Tiny Invader and the Mighty Moose." The story, authored by DNR biologist Pat Karns and research assistant Sharon Barton, offers this explanation for the revival: "The forest has now grown back and become less favorable for deer and for spreading the parasitic worm they carry. It seems obvious that we cannot expect to carry large populations of moose and deer on the same range because of this tiny nematode worm."
But by the 1960s, fretting over moose disease had been replaced with concerns over too many moose for the available habitat. Aerial counts showed as many as four moose per square mile in Lake, Cook, Marshall, Beltrami, and Kittson counties, according to a 1967 report in the Volunteer. The report noted, "Food conditions for moose are deteriorating as a result of this heavy pressure." The news was delivered to readers at the behest of the DNR and the U.S. Forest Service, which both advocated a moose-hunting season. Noting the success of the state's carefully managed deer seasons, the report recommended applying "these same management policies to our moose population before nature applies her own ruthless laws of population control—starvation, disease, and lower reproduction."
Moose hunting returned to Minnesota in 1971. The season established by the Legislature requested that hunters apply for permits in groups of four, and only one moose was allowed per party. More than 37,000 hunters applied, and 400 parties were selected for the hunt. That first season 374 moose were harvested.
Areas open to moose hunting and the number of permits given out for the hunt grew throughout the 1970s. During the 1983 season, hunters took a record 1,179 moose. A small news item in the Jan.–Feb. 1984 issue touted Minnesota as offering the best opportunity in the lower 48 to bag a moose.
But in the early 1990s, the moose population in the northwestern part of the state began to decline. The region's once stable population of about 4,000 moose continued to dwindle, and hunting in northwestern counties ended after the 1997 season. By 2007, the last time a survey was conducted in northwestern Minnesota, only 100 moose remained. No single cause for this decline was determined, though DNR research did discover that cows in the northwest had a low pregnancy rate of 55 percent, compared to a typical rate of 83 percent in other North American moose populations. Poor nutrition, parasitic liver flukes, and warmer summer temperatures may have also contributed to the moose population's collapse, according to a DNR study.
The current moose population in the northeast has been showing signs of trouble for more than a decade. Research was first intensified there in 2002 when a study by wildlife researchers Mark Lenarz of the DNR and Mike Schrage of the Fond du Lac Band began tracking 116 radio-collared moose. Those monitored moose exhibited a 21 percent average annual mortality rate—twice the rate for North American moose and troublingly identical to the estimated rate of the already diminished northwestern herd. Cars and wolves were responsible for a large share of the mortality, but 49 percent of the deaths couldn't be directly attributed to any single cause. "Tipover disease" was the moniker given to the mysterious deaths of seemingly healthy adult moose.
One promising difference was uncovered by this research: Moose cows in the northeast had an average pregnancy rate of 84 percent, much better than the northwestern herd's. But not enough calves are reaching adulthood to slow the moose population's downward trajectory. In May of 2013, a technological advance allowed DNR researchers to begin outfitting newborn moose with GPS tracking collars in an attempt to find out why. Collaring of moose was halted this spring due to concern that cows were abandoning too many of the calves that were collared by researchers.
Ahead of the calf collaring in 2013, 111 adult moose were outfitted with GPS collars. Another 68 adults were collared during the winters of 2014 and 2015. Currently, 93 of those adult moose are still being tracked with the collars, which have a five-year battery life. These collared moose will allow researchers more time to examine the various causes of adult moose mortality and annual survival.
Being able to watch the movements of moose in real time via GPS has also provided new insight into the maternal behavior of moose. These observations could allow continued study into the survival rates of moose calves without having to collar them, according to the DNR's Glenn DelGiudice, who heads up the calf mortality study.
Adult female moose typically move 50 to 300 meters in an hour, but cows on the verge of giving birth take a hike. "All of a sudden they make their calving move," says DelGiudice. They move, on average, 5½ kilometers in 14 hours. "Then they drop down to 20 meters per hour." Calves are typically born within 12 hours of this slowdown. Researchers are confirming the births of calves by inspecting the sites where the cows stopped.
Moose cows also exhibit relatively predictable behavior when a predator kills a very young calf, says DelGiudice. The cow will flee, "but then she makes one or more return visits over the next several days," he says. "So we'll go in and determine whether or not there was a kill. What we're finding is that if [the cow] doesn't make return visits, her calf may have been old enough to go with her and may have gotten away."
Should the downward trend continue for northeastern Minnesota's moose population, researchers project that these animals could be gone from the state by 2025. DNR researchers continue to look for better ways to understand what combinations of factors are preventing moose from thriving. Because deer are the primary carriers of the harmful Parelaphostrongylus tenuis parasite, the agency believes it is prudent to continue maintaining a low deer population (less than 10 per square mile) in northeastern Minnesota's moose range. With increased funding, the DNR and other conservation organizations are ramping up efforts to create favorable moose habitat in Cook, Lake, and St. Louis counties.
For decades, in fall and winter, the DNR has been shearing small 10- to 40-acre sites that are heavy with upland brush and tree species. The activity creates good moose browse for about 15 years, according to Nancy Hansen, DNR area wildlife manager in Two Harbors. These projects leave mature trees standing to provide cover in winter and important shade for moose during hot summer months. Prescribed burns, mostly on federal land, have also benefited moose by providing fresh browse.
More habitat projects are in the works to create or enhance moose habitat on some 8,500 acres in northeastern Minnesota, thanks to the Minnesota Moose Habitat Collaborative. The collaborative, spearheaded by the Minnesota Deer Hunters Association, works in partnership with the DNR, the University of Minnesota Duluth, and The Nature Conservancy, as well as tribal, county, and federal authorities. To date, the group has secured about $3.7 million from its partners, including nearly $3 million from the Clean Water, Land and Legacy Amendment's Outdoor Heritage Fund.
"We are all concerned about the moose, and we don't want to see them disappear," says Hansen. "Every little thing we do to help them is a good thing."
