Serving Northern St. Louis County, Minnesota

Moose numbers remain stable

Yet still no sign of a population rebound

Marshall Helmberger
Posted 2/21/18

REGIONAL– It appears that moose numbers have stabilized in northeastern Minnesota, but still show no sign of recovery from declines experienced from 2006-2013.

“While the population appears …

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Moose numbers remain stable

Yet still no sign of a population rebound

Posted

REGIONAL– It appears that moose numbers have stabilized in northeastern Minnesota, but still show no sign of recovery from declines experienced from 2006-2013.

“While the population appears stable, low numbers of moose are still a major concern for the DNR,” said DNR Commissioner Tom Landwehr. “We continue to pursue the best science, research and management tools available to us to help Minnesota’s moose.”

The 2018 aerial moose survey estimated 3,030 moose in northeastern Minnesota. That’s lower than last year’s estimate of 3,710 moose, but DNR researchers point out that natural variation inherent in such surveys makes the difference from last year statistically insignificant. Researchers note that they will never see and count all of the moose across the 6,000-square mile survey area, which means the survey number is always on a statistical model, rather than a hard count. Statistically, the DNR is 90 percent certain that the population is somewhere between 4,140 and 2,320 moose.  

This year’s result showed no major change in the closely-watched calf-to-cow ratio, which is an indicator of reproductive success. This year’s ratio of 0.37 calves per cow is similar to the ratio the last few years, but is somewhat higher than the ratios seen during the most dramatic decline in the moose population, when barely one in four cows had a surviving calf during the annual January survey.

“The stability of moose numbers in recent years provides a reason for some optimism – after all, we’re not facing a significant decline,” said Glenn DelGiudice, DNR moose and deer project leader. “But this year’s results would be more palatable had they reflected the beginning of a turnaround in the population trend.”

This year’s survey also recorded 1.25 bulls for every cow spotted by researchers, a relatively high discrepancy. Generally, a species like moose tends to have slightly more females than males. Over the past ten years the bull-to-cow ratio has ranged from 0.64 to 1.25.

Reproductive success and adult survival have the greatest impact on the moose population over time.

“Our field research has shown that annual pregnancy rates of adult females in this population have been robust,” DelGiudice said. “But it is a challenge to maintain a high number of adult females that can become pregnant, produce calves and rear them to one year of age.” 

Survey results also indicate that calf survival to January has been relatively stable, but consistently low. Field studies have indicated that it is even lower by spring, translating to low numbers of moose calves living through their first year. Importantly, the DNR’s detailed investigations have shown that wolf predation has consistently accounted for about two-thirds of the calf mortality compared to one-third of the adult mortality.   

Annual aerial moose surveys have been conducted each year since 1960 in the northeast.  Adjustments were made in 2005 to make the survey more accurate and annual results more comparable.

This year’s survey involved flying in 52 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.

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