Researchers trying to solve the riddle of what's killing Minnesota's moose are getting useful data from radio collars they've attached to adult animals. But collared calves are providing little information – partly because they're often abandoned by their mothers.
The Duluth News Tribune reports of the 25 newborn calves collared by the Department of Natural Resources last May and June, 19 either shed those collars or were abandoned. The remaining six were killed by predators, usually wolves.
The DNR's lead moose researcher, Glenn DelGiudice, tells the News Tribune the results are frustrating, but says researchers have made adjustments and plan to collar more calves this year.
The GPS radio collars are part of the agency's study of what's caused the state's moose herd to shrink by 60 percent in less than a decade. Last week's numbers from the most recent moose count showed no change in the morbid trend.
Collars on adults yield data
The DNR says 2014 saw fewer deaths among adult moose wearing radio collars than in the first year of the study. 20 percent died in 2013, which is double the mortality rate in a stable moose population. Last year 11 percent died, the DNR says.
In each year just over half the adult deaths were caused by predators – sometimes bears but more often wolves. Nearly half were caused by various health problems including brainworm, bacterial disease, or (in the study's first year) winter ticks.
DNR wildlife research manager Lou Cornicelli tells the St. Cloud Times Minnesota's loss of moose is not explained by the increase in wolves. Cornicelli points to northwestern Minnesota, which is not wolf country but has lost virtually all of its moose. "There's more to it and there's no doubt moose would be declining even with the absence of wolves," he tells the Times.
New approach to collaring calves
Collared moose calves that were abandoned by their mothers last year were then rescued by the DNR and turned over to the Minnesota Zoo.
The agency hopes it won't have to do that this year. DelGiudice tells the News Tribune research teams have made adjustments.
This time around the newborns will be collared by no more than two researchers, who will approach on foot rather than by helicopter, and will stay less than 10 minutes.
The hope is that the less intrusive visits will make the cows less likely to reject their calves.