Northeastern Minnesota's moose population dropped again over the past year, continuing a troubling trend of rising moose deaths and declining births.
The Minnesota Department of Natural Resources reported Monday that the state's estimated moose population slid from 7,600 animals in 2009 to 5,500 this year.
Though weather and snow conditions on the ground can cause wide variations in the annual survey totals, DNR wildlife officials say the numbers don't look good for the long-term viability of Minnesota's biggest north woods animal.
"I'd probably say that last year's [higher number] and this year are the aberrations and what we really would have seen if we had a precise [population] estimate is a more gradual decline over the last four or five years," Mark Lenarz, the DNR's forest wildlife program leader, told the News Tribune. "We didn't lose 2,000 moose over the last year. But we do see this continued trend in declining number, especially with calves, that has caused the concern in recent years."
The population estimate comes after an aerial survey in January of 40 of the state's 450 moose management plots, randomly selected each year across St. Louis, Lake and Cook counties.
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Among the most troubling findings of this year's annual winter survey was the low rate of only 28 calves per 100 cow moose, an all-time low since the survey started in 1960. The long-term average when the population was healthy was 60 calves per 100 cows, Lenarz said.
The decline of the Northeastern Minnesota moose herd has been happening for about 13 years and comes on the heels of the virtual disappearance of Minnesota's northwestern moose herd -- from more than 4,000 moose 20 years ago to fewer than 100 today.
A study of radio-collared moose in Northeastern Minnesota between 2002 and 2008 determined that non-hunting deaths were much higher for Minnesota moose than in moose populations in other areas. Scientists say that higher death rate is from many different factors, including disease and parasites, but that most of the factors have been spurred by warmer temperatures. Minnesota is at the southern extreme of the moose range, and some say a warming climate may eventually push them north, out of the state.
Of 150 adult moose radio-collared since 2002 in Minnesota, 103 have died, most from unknown causes thought to be diseases or parasites. Nine moose died as a result of highway vehicle accidents. Two were killed by trains. Only six of the collared moose were killed by wolves.
"Moose are superbly adapted to the cold but intolerant of heat," Lenarz said. "And scientists believe that summer temperatures will likely determine the southern limit of this species."
In August, a state moose advisory committee convened by the DNR released its findings, which will be used in the development of a new DNR moose plan. The committee indicated that while climate change is a long-term threat to the moose in Minnesota, some moose probably will survive in the state for the foreseeable future.
