Updated 4:50 p.m. | Posted 12:01 p.m.
After years of deep and worrisome declines, Minnesota's moose population is showing signs of stabilizing — but that doesn't mean the creatures are out of the woods yet, state conservation officials said Monday.
The state estimates 3,710 moose live in the northeastern part of the state based on aerial surveys done last month. That's statistically unchanged from the estimate of 4,020 a year ago, the Minnesota Department of Natural Resources said, noting the inherent challenge of trying to count every animal.
"At this point, results do not indicate that moose are recovering in northeastern Minnesota," DNR moose project leader Glenn DelGiudice said in a statement.
"While it is encouraging to see that the decline in the population since 2012 has not been as steep," he added, "the apparent stability does not allow us to forecast the direction of the population's trajectory into the future."
The DNR said research suggests the "recent signs of stability could have resulted from higher calf survival." Calf survival in recent years has reached 40 percent, compared to only 24 percent when the DNR launched a moose calf mortality study in 2013.
Adult moose have also survived at slightly greater rates in recent years. The DNR said its moose mortality research project shows that survival of adult moose has remained between 85 and 88 percent from 2014 to 2016, a bit higher than the average of 81 percent during 2002 to 2008, and 81 percent in 2013.
Each year the population estimate is compared to 2006, because the state's highest moose population estimate of 8,840 occurred that year. Currently, northeastern Minnesota's moose population is estimated to be 58 percent lower than in 2006, the DNR added.
The DNR launched a landmark study four years ago to try to determine what is killing the state's moose at such an alarming rate. Much remains unknown. "What is known: Factors including infections, parasites and other health issues are killing moose and predisposing them to being preyed on by wolves," the department said.
Researchers are heartened by the recent stability of the moose population, but the DNR has seen a similar pattern before on the opposite side of the state, in the moose herd that used to number more than 4,000 animals in northwestern Minnesota.
In the mid-1980s, DelGiudice said in an interview, that herd's population began to decline. But it wasn't a consistent drop.
"It would have short, multi-year intervals of stability," he said, "and then a sharp decline. Then another short interval of stability, and then a sharp decline."
Ultimately, the northwestern herd entered a steep, final plunge that resulted in fewer than 100 moose by 2007.
DelGiudice stressed the herd in northwest Minnesota differed in significant ways from the population in northeastern Minnesota.
The habitat on the western side of the state included more wetlands and agricultural land, whereas the landscape in the Arrowhead region more closely resembles the moose's core range in Canada.
Still, he said the DNR is not ignoring the pattern.
"I do think there's a lot of reason to be concerned about the future if we don't take some steps to turn things around for moose," said Mike Schrage, a wildlife biologist with the Fond du Lac Band of Lake Superior Chippewa who helped with the survey.
Schrage said issues like climate change, wolf predation, habitat loss caused by a decline in timber harvesting, and deer populations all have impacts on Minnesota's moose.
"I'm glad to see things have stabilized," Schrage said. "But it would have been nice to see a few more. That's what most people would like to see with our moose herd — numbers going back up."