August 01, 2017

The 2017 Michigan DNR moose survey indicates an encouraging modest increase in the core area of the west central U.P. moose range. This year’s moose population estimate indicated 378 moose in the core population area; up from 285 in 2015. This is a good sign since the 2015 moose population survey indicated a 28 percent population decline.

Dr. Dean Beyer of the Michigan DNR Wildlife Division monitors the Michigan moose population. In a February interview, Beyer said their “wildlife staff had completed the aerial moose survey in the core high density plots of the primary moose range.” He went on to say melting snow conditions hampered the staff’s visibility of moose against the snow which caused them to curtail the survey before completing the low density plots. Good snow cover makes the moose stand out against the background vegetation and cover.

“As a result, an overall population estimate could not be generated in direct comparison to previous surveys” Beyer said. Instead, Wildlife Division staff calculated a population estimate trend for just the high density plots over time. Beyer said “in the past, the core zone supported 80 to 90 percent of the moose population.” He continued, “The western U.P. moose range covers about 1400 square miles in parts of Baraga, Iron, and Marquette Counties.”

This year’s survey indicated a moose population of 378 moose compared to only 323 in 2015 and 451 in 2013. The DNR researchers believe if the survey would have been completed on the entire western moose area, it would have “yielded a population estimate of between 420 to 470 animals.” Beyer stated “from 1997 to 2007 the U.P. moose population was growing by 10 percent a year.” He went on to say that “from 2009 to 2013 the moose population only grew by two percent per year.”

Beyer explained the DNR’s survey efforts have been focused on the western UP moose population that was re-introduced in the “Moose Lift” program. Beyer explained that the moose herd in the eastern U.P., “likely number fewer than 100.” The source of the eastern UP moose is not known for certain. It is possible that a few scattered moose remained from native moose, although it is also likely some moose immigrated from eastern Ontario or the western U.P. Moose also maintain a strong population in Michigan’s Isle Royale National Park.

This year’s moose population estimate indicated 378 moose in the core population area; up from 285 in 2015. Bill Ziegler photo

The research biologist said the ratio of moose calves to cows in the population is an important parameter. He stated, “In recent years, this ratio averaged 59 calves per 100 cows and was consistent with estimates of calf production and survival determined by monitoring radio-collared cows from 1999-2005. The calf to cow ratio increased slightly to 47 calves per 100 cows this year after dropping to 42 per 100 cows last survey.”

In 2011, the DNR Moose Hunt Advisory Council, a legislatively created council, investigated the potential of a moose hunt in Michigan. The council felt a moose hunt was a feasible option provided the moose surveys indicated that the moose population continued to grow at a sustained growth rate of over three percent per year.

In recent years, concern has been growing among wildlife management agencies across the southern tier of the US moose range. Minnesota has had a stable moose population with a carefully regulated hunting season for many years. According to the Minnesota DNR, their moose population has dropped 52 percent since 2010. On the southern tier of the moose range state wildlife conservation agencies like New Hampshire and Montana have also reported a decline in their moose population.

The Minnesota DNR reports they had two geographically separate moose populations. The northwest Minnesota moose population dropped dramatically since the 1990s from about 4000 down to about 100 recently. The northeastern Minnesota moose population is also dropping from a recent high of about 8000 as recently as 2006, down to about 3000 in 2013.

Although a number of factors are likely to have contributed to Minnesota’s moose decline, Minnesota DNR suspended their 2013 moose hunting season as a precaution. Tom Landwehr, Minnesota DNR Commissioner, said “it is now prudent to control every source of mortality we can as we seek to understand the causes of population decline.”

Minnesota DNR wildlife researchers are currently conducting a comprehensive study to determine the factors that have led to a major decline in their moose herd.

Early results indicate there are several factors affecting the Minnesota moose population decline. Lou Cornicelli, Minnesota DNR Wildlife Research Manager, said “preliminary results indicate the factors likely causing the decline are complicated”. It appears that a combination of parasites/disease and wolf predation, are important causes they have found so far.

Their early research indicates that about one third of the adult moose mortalities are from wolf predation. Although it is important to note that 33 percent of the wolf predated moose had underlying health conditions that likely made them more vulnerable to predation. Minnesota moose researchers are currently focused on moose calf survival rates and moose nutrition. Recent moose calf mortality study indicated wolves killed about 75 percent of the 40 calves that were collared for the study.

Additional Minnesota moose research indicates that the warm winter weather stresses moose nutrition. It appears the more time winter temperatures are above 23o F moose do not eat enough to remain well nourished.

Although the 2017 moose population appears to be up modestly, there is still concern about long term U.P. moose population trends. Retired Michigan DNR Moose Biologist Rob Aho said “the moose have not filled all the available U.P. habitat”. A good qualitative indicator that moose have reached their population potential would be when the moose occupy the entire good moose habitat. Future moose population surveys will be necessary to identify any long-term trend for Michigan’s moose population.