The Uncertain Future of the Minnesota Moose Population
Biologists are scrambling to help moose survive against ticks, deer worms, wolves, and bears. But is it too late?
The bad news: According to the Minnesota Department of Natural Resources, the state’s moose population fell 66 percent between 2006 and 2013, from 9,000 to under 3,000. The better news: For the nine years since, the population has remained stable. But state leaders and scientists are still scrambling to help the herd survive. And their greatest worry is a formidable foe: climate change.
Decades of milder winters have set into motion a chain of consequences that land heavily on the largest member of the Cervidae family. First, the tick population goes up. While lower numbers are more typical, researchers have encountered some moose with thousands of ticks on them, and observed that the corresponding discomfort distracts the inflicted animals from more important things, like nutrition and their calves. One result having to deal with ticks through the winter and “ghost moose,” animals that have scratched themselves hairless and often starve to death.
Less snow, meanwhile, is more favorable for whitetail deer, which have significantly increased their numbers in the North Star state’s moose territory. While this may introduce some food competition, the greatest impact is parasitic. The deer have a symbiotic relationship with the brain worms they carry around in their skulls. Unfortunately for the moose, which never evolved the same relationship, the deer disseminate the worm eggs when they defecate and the larvae end up on vegetation that the moose consume. More dead moose.
“About 25 to 35 percent of moose that die in a year are dying because of brain worm,” Grand Portage Band biologist Seth Moore told KBJR-TV 6 in Duluth.
And it’s not just the deer and the worms and ticks. Wolves and bear follow the deer; and wolves and bears eat the moose. “By collaring the calves, we’ve been able to determine that 80 percent of calves are preyed on by bears and wolves in the first two weeks of life,” adds Moore.
It’s a daunting set of threats. But Moore and his colleagues have responded with a bundle of countermeasures. From a helicopter, they tranquilize moose below, then swoop in to administer a COVID test; take blood, urine and stool samples; count and treat ticks; conduct an ear biopsy; and finally tag and collar the sedated moose.
The team has collared 170 moose over the past 12 years in hopes that their interventions and studies can save the herd. They are also lobbying the state to allow more aggressive deer and wolf hunting, and to conduct more prescribed burning to reduce tick levels. “We need to address the moose population decline quickly and aggressively,” Moore said. “If we lack the societal will or the legislative will, I don’t see how moose populations will recover.”