Nature’s majesty

The history of Isle Royale’s moose population


108: A female moose feeds on the shore of Lake Superior at Isle Royale National Park.

93: A Native American pictograph found near North Hegman Lake in Minnesota, in the  Boundary Waters Canoe Area Wilderness. It’s believed to have been painted 500 to 1,000 years ago.

45: A bull moose rests in the summer grass at Yellowstone National Park.

271: A moose release on the  Peshekee Grade in Marquette County circa 1985.

270: Another moose release on the Peshekee Grade, this time in 1987.

Story and photos by Scot Stewart

On the mainland of the Upper Peninsula things are a little different. Moose have not thrived the same way they have on Isle Royale. They were once found throughout nearly all of Michigan except the far southwest corner. They disappeared from the Lower Peninsula around 1889, and may have become extinct in the Upper Peninsula too.

The changes brought by logging here drove out the woodland caribou. White-tailed deer slowly extended their range northward, following logging activity to fill the niche.  In the southern U.P. snowfall was not a huge issue for white-tails and they thrived, especially along the edges of farming areas. In the northern areas, the deer relied on the winter logging activity to clear paths for them to move, avoiding extensive travel through deep snow between feeding areas, where slash from logging provided lots of browse, especially in cedar swamps, and bedding areas in stands of pine, hemlock and cedar where there was less snow and warmer temperatures.

In the 1930s biologist began exploring the idea of bringing moose from Isle Royale to the mainland to establish a population of the large ungulates on the mainland.  During their higher density years on Isle Royale, moose were captured and brought to the mainland. The transfer of Isle Royale moose came before the island achieved national park status.  Moose numbers were high and the animals were not in very good condition, but 71 were trapped between 1934 and 1937 from Isle Royale.  63 moose were released in Marquette, Keweenaw and Schoolcraft counties.  The other eight went to the Detroit Zoo and to the Cusino Research Station in Shingleton where their natural history was studied.

Due to the poor condition many of the moose were in when caught, they did not fare well. Infections, poaching and possible cases of brainworm took their toll. Little was seen of moose during the 1950s and ’60s, and the few that were seen probably had crossed over the border from Ontario near Sault Ste. Marie.

Biologists continued to monitor improving habitat conditions for moose in the U.P., especially the western counties, and a plan was developed to make a second attempt at bringing in moose, this time from Canada. With Isle Royale a national park, a new source for moose was found in Canada – Algonquin Provincial Park, in exchange for wild turkeys.

In 1985, 29 moose were captured in the park, 19 females and 10 males.  Darted with tranquilizers from the air, the moose were lifted by helicopter to a lake edge where they were crated and trucked to a site on the Peshekee Grade in western Marquette County. Because of the early January timing, many females were pregnant with the hope of quickly adding to the 29 in springtime. The plan worked, with 21 calves born that spring.  While the numbers did not rise as quickly over the next two years, Moose Lift, as the project was called, was considered enough of a success to make a second attempt to add to the herd. Thirty more moose were brought over in Moose Lift II in 1987.  The Michigan DNR continues to monitor the herd, and while it has not grown as fast as first hoped, the moose population has grown.

In January of 2017 Michigan DNR biologists estimated the moose population in the western Upper Peninsula at 378, up from 285 in 2015. This estimate is constructed from aerial surveys over areas covering parts of Marquette, Baraga and Iron counties surrounding the location of the moose releases in 1985 and 1987 near the McCormick Wilderness.  A second population of moose in the eastern U.P. is thought to contain less than 100 individuals. It has not been surveyed since 1991 as they are spread out so thinly they are difficult to find by foot or air.  Moose in the eastern U.P. are believed to have crossed the St. Mary’s River from Ontario.

Their aerial survey involves flying over specific areas called plots and counting the moose they see during winter flights when the moose stand out against the snow.  Some plots are known to be home to higher densities than others so they provide the bulk of the data needed.  As the biologists look for trends, the percentage of females with calves is important to gage population growth and health. The estimated dip in the 2015 population was supported with moose with calf rates at 22, 17 and 19 percent for the years 2013, 2015 and 2017.

There are lots of small factors challenging moose in the Upper Peninsula. Their success is dependent on many details in their environment. Deer are one of those factors. Deer harbor a parasite, brainworm, Parelaphostrongylus tenuis. While this nematode worm’s effects on white-tailed deer is minimal, for moose the parasite’s presence is usually fatal, attacking neurological tissue.

Global warming is another factor playing heavily into the management of moose. The moose are hindered by winter ticks.  Warm, early springs can melt snow before the ticks drop off the moose.  If the ground is bare, they can lay eggs and continue to maintain a presence in the area.  With snow cover presence when they fall off, they don’t survive.

Currently the Michigan DNR is managing forest stands in a compartment system according to biologist Brian Roell. Stands are cut in a 10-year cycle with half cut at a time to provide openings for new grow of aspen, birch, fir and other moose food. Cover pockets are left in these cuts to provide areas where moose can seek shade during warm periods while they ruminate.  Warmer summer have made these “loafing areas” important places for the moose to stay cool.

The metabolism of moose is tied to climate too. They prefer a cooler climate and with the increase of average summer temperatures, cooler areas may be crucial to their summer health and the health of new calves. “You look at us on the southern edge of their range and you deal with climate issues as the hot summers affect calf production”, Roell explained in a recent phone interview.

Wolves are not considered an important factor in moose mortality in the western U.P.  In many areas where moose are currently found, the deep winter snow depths prevent high white-tailed deer densities. That not only reduces the contact with brainworm, the parasite the deer can carry, but it also – reduces the incidence with wolves as they concentrate more in areas with more deer, an easier prey for them.  A recent outbreak of distemper has occurred in the local wolf population, reducing their numbers and their predation impact. There is one known moose killed in that area by wolves recently.  It was stunted, had a bad leg, was blind in one eye and had brainworm. Mortality via automobiles is more common, with several moose mortalities reported in most years in the U.P.

Two parasites are also problems for western U.P. moose. As mentioned, winter ticks attack moose during cold weather months. Not only do they weaken moose by feeding on their blood, they cause itching.  In response, the moose rub their hind legs against trees often wearing down their fur, increasing heat loss. Winter ticks were brought to the U.P. on the moose imported from Canada.

Western U.P. moose also suffer from liver flukes, a parasite picked up when they accidently ingest snails in and near water containing the flukes. The flukes also weaken the moose who wall up the flukes in cysts in a response to their presence in the liver and make the moose more susceptible to other ailments.

It is possible to drive up on the Peshekee Grade and find moose tracks on the road after the pavement ends, and occasionally see a moose from the road. They are also seen along M-95 between U.S. 41 and Republic. Moose warning signs on the highways have been frequently placed near sites of moose-car collisions.  At least four moose have wandered into Marquette’s city limits in recent years, including a bull who spent a week in Park Cemetery and a female with a calf and a bull who made it onto Presque Isle.  Big Bay also sees moose occasionally around town.

On Isle Royale, their part in the natural history of the park is a prime reason people visit.  Their place in the web of life across the Upper Peninsula is important in maintaining a healthy ecosystem and their presence is a true treasure for those having the honor of a view of this majestic, BIG animal!


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