A CAPTURED MOOSE rests with its eyes covered as a wildlife researcher works around it during a previous Michigan Department of Natural Resources collaring effort. (Michigan Department of Natural Resources)

The 1,000-pound Michigan bull moose — standing 6 feet, 5 inches tall with 40-pound, paddle-like antlers — is the iconic symbol of the Upper Peninsula’s wildness.

Despite their majestic status, Michigan’s moose have faced significant challenges over the past century. To understand the factors shaping their survival today, researchers are examining population trends and the hurdles moose encounter.

“Michigan’s moose are a vital part of the Upper Peninsula’s ecosystem and identity,” said Tyler Petroelje, northern Michigan wildlife research specialist for the Michigan Department of Natural Resources. “Through this new study of factors limiting moose population growth, we’re working to uncover a clearer path for the future of moose in Michigan.”

Aerial survey

DNR wildlife biologists have conducted aerial surveys to estimate the moose population in the western U.P. since 1997. Every other year in January, survey planes fly low in a grid pattern over Marquette, Baraga and Iron counties as researchers record the number of moose spotted.

A MOOSE ON a trail camera in the Michigamme Highlands as part of the ongoing Michigan Department of Natural Resources Wolf Abundance Survey. (Michigan DNR and Michigan State University)

Doing the survey in winter makes it easier for trained spotters to see moose against the leafless, snowy landscape, but it’s still impossible to count every moose. Instead, the numbers are adjusted using a statistical model to estimate the population.

The 2023 U.P. DNR moose survey showed a population of 426 moose in the western part of the region. The 95% confidence interval estimates a range between 334 and 518 individuals.

In addition to the regular aerial survey, researchers will begin a new project later this month to explore the reasons behind the slowed moose growth rate.

The full name of the study is “Factors limiting moose population growth in the western Upper Peninsula.”

New moose study

A MOOSE IS transported by a helicopter in Canada during the 1980s Moose Lift operations to re-establish moose in Michigan's Upper Peninsula. (Michigan Department of Natural Resources)

Through this new effort, the DNR, Keweenaw Bay Indian Community and Northern Michigan University will work together to try to better understand the trends and challenges the Michigan moose herd faces.

“As co-stewards of our shared land and natural resources, the Keweenaw Bay Indian Community welcomes the opportunity to work with the DNR and NMU to help answer important questions about the Michigan moose population,” said Erin Johnston, wildlife and habitat manager for the KBIC Natural Resources Department in Baraga.

Researchers anticipate fitting 60 moose with new tracking equipment over the next two years. During this first year of the study, 20 moose will be captured and equipped with radio collars that will provide precise location data.

Tracking these movements will help researchers understand moose survival and causes of mortality, pregnancy rates and birthing events.

“There is a need to examine why moose population growth in the Upper Peninsula has been stagnant over the past decade,” said Diana Lafferty, associate professor in biology at NMU. “As such, measuring vital rates like reproduction, survival, immigration, emigration, as well as identifying factors that may be limiting moose population growth, such as parasites, disease, predation, vehicle collisions and habitat alteration, are essential for understanding and modeling population dynamics.”

A MOOSE ON a trail camera in the Michigamme Highlands as part of the ongoing Michigan Department of Natural Resources Wolf Abundance Survey. (Michigan DNR and Michigan State University)

During the capture operation, spotter planes will report moose locations to nearby helicopters and ground crews. Moose will be sedated and crews will move in quickly to collect biological information and fit the moose with a tracking collar.

The captures will take place in mid-to-late February, depending on weather and other conditions, across the western moose range, in an approximately 500-square-mile block across the Michigamme Highlands.

“For the safety of moose, researchers and others, we are asking the public to please avoid the area where the helicopter and snowmobile ground crews are operating,” said John Pepin, DNR deputy public information officer. “Before those activities start, we want people to know what will be happening, and just as we recommend for moose sightings and photography — keep a safe distance away.”

History of moose in Michigan

Moose once occurred throughout much of the state. But European settlement led to unregulated hunting and habitat loss, with moose disappearing from the Lower Peninsula and their numbers declining to just a few scattered individuals in the Upper Peninsula by the early 19th century.

After a failed reintroduction attempt in the 1930s, a new project began in the 1980s, fondly known as the “Moose Lift.” Fifty-nine moose were transported by helicopter and truck from Algonquin Provincial Park in Ontario, Canada, to northwest Marquette County.

The goal of the moose reintroduction was to produce a self-sustaining population of free-ranging moose in the Upper Peninsula.

Nearly 40 years later, the moose population in the western part of the region where the translocation occurred has grown to more than 400 but is still well below an initial projected goal of 1,000 animals by the year 2000.

Over the last few decades, researchers have observed two very different periods of population growth. During 1997-2007, the population grew steadily by 10% each year. But data from the biennial aerial population surveys shows that annual growth has slowed to less than 1% since 2009.

In addition to the study area in the western U.P., a smaller moose population remains in the eastern U.P., found primarily in Alger, Schoolcraft, Luce and Chippewa counties.

No formal surveys of the eastern U.P. moose population have been conducted, but biologists have documented resident moose and reproduction in parts of the east U.P., based on field observations and reports from the public.

Moose are also found in Keweenaw County at Isle Royale National Park, a population managed by the National Park Service.

Why moose matter

Understanding the factors that limit the moose population is crucial for land and wildlife managers, as it provides insight into the broader ecological health of the Upper Peninsula. Furthermore, moose are culturally significant, as they are a symbol of Michigan’s wilderness and an important species for the traditions and practices of Indigenous communities in the region.

Moose are the largest native deer species in Michigan and have a complex role in the ecosystem. As large herbivores, they shape the structure of forests through their feeding habits, which includes browsing on trees such as aspen, birch and balsam fir.

“Both the presence and absence of moose can affect forest growth, creating cascading effects throughout the habitat, impacting deer, birds, insects and plant life,” Petroelje said. “As a keystone species, moose have a disproportionate impact on their environment compared to most other species.”

Researchers are looking at several hypotheses for what is limiting the Michigan moose population. Historically, the pregnancy rate has been lower than the North American average by about 13%.

The western U.P. population also has low rates of twin calves being born, which can be a signal that the moose population is nearing the number that can be supported by the region’s environment.

Parasites and disease are among the hypotheses for what is limiting the population as well. Brainworm is a lethal nematode carried by white-tailed deer. Although brainworm has little effect on white-tailed deer, it can cause a fatal neurological disease in moose.

Additionally, Michigan moose are at the southern edge of the moose range. Parasites and warmer temperatures may lead to increased stress and lower levels of reproduction.

“Moose are adapted to cold climates due to their large size and thick fur,” said Brian Roell, a DNR wildlife biologist in Marquette. “The mixed forested areas with wetland complexes found in the Michigamme Highlands are ideal habitat.”

Over the past decade, moose-vehicle collisions have become more common. During the past three years alone, the DNR received reports of 47 moose being struck and killed by vehicles.

Though wolves are large enough to take down an adult moose, previous studies of moose survival in mainland Michigan show predation by wolves was not an important factor in adult moose mortality.

“However, predation has been found to be important to calf survival regionally, like in Minnesota, which is experiencing similar limited population growth,” Petroelje said.

Though moose are considered a game species in Michigan, there has not been a moose hunting season since the 1800s. To support the continued growth of the population, the Moose Hunting Advisory Council recommended only allowing a moose hunt if the population maintains 3% annual growth.

By studying moose population trends and the challenges they face, wildlife managers can better understand the interconnectedness of species and ecosystems. This knowledge helps create better management strategies, ensuring that moose and the ecosystem at large thrive.

For more information on moose in Michigan, go to Michigan.gov/Moose.