This year’s population estimate of 3,290 moose marks a decade of Minnesota’s moose population remaining relatively stable, according to the results of the Minnesota Department of Natural Resources’ 2023 aerial population survey.
Although the estimate dropped from 2022’s estimate of 4,700, the change continues to reflect the population stability observed in previous years. After a decline from a population estimate of approximately 8,000 in 2009, Minnesota’s moose population appears to have stabilized at about 3,700 animals in recent years.
Stabilized doesn’t mean the population is constant, said John Giudice, DNR wildlife biometrician. Instead, annual changes since 2013 appear to be relatively small on average and random, with some years showing a population increase and others a decrease.
Although survey results suggest a decrease in the moose population from 2022 to 2023, those estimates are better used to understand long-term trends. Factors such as visibility of moose from the air, challenging weather conditions and moose avoidance of aircraft create moderately high sampling uncertainty. That uncertainty makes it difficult for researchers to make confident statements about the magnitude of annual population changes unless those changes are relatively large.
But data collected recently by researchers with the Grand Portage Band of Lake Superior Chippewa suggest the magnitude of this year’s decline could be more than an artifact of sampling. They have reported high mortality rates on collared moose and similar decreases in aerial surveys around Grand Portage and Isle Royale. Continued comparisons in coming years will help answer that question.
The 2023 DNR survey results showed that calves comprised an estimated 16% of the population and the estimated calf-cow ratio was 38 calves per 100 cows. Those estimates are slightly lower than last year’s figures but are comparable to values observed during the last 10 years, especially considering moderate-to-high levels of sampling uncertainty. Both factors are key indicators of reproductive success.
While estimates suggest continued stability in the population and reproductive success, DNR researchers point out that Minnesota moose remain at risk given long-term trends
Both the Fond du Lac Band of Lake Superior Chippewa and the 1854 Treaty Authority contributed funding and personnel for the 2023 annual survey. The survey is available on the DNR’s moose management page (mndnr.gov/moose).