climate change

With Ticks Feasting on Moose, Vt. Researchers Look to Help

A multi-year study is underway into the health of Vermont's moose herd

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Research underway in Vermont is aimed at supporting the state's struggling moose herd, which has been suffering from an increase in winter ticks — which scientists say have been doing better in milder winters.

"We lost a lot of calves last winter," said Nick Fortin, a moose biologist with the Vermont Fish & Wildlife Department.

Fortin is part of a multi-year study into the health of the state's largest wild animals. Moose are iconic in northern New England, but for years, they've been under stress.

Many moose have been found infested with winter ticks in massive clusters, with such ravenous appetites for blood that their unwilling hosts are left severely underweight, scratching themselves so hard they can rub their hair right off.

Some scientists have compared the plight of moose to how humans would feel if we donated a pint or two of blood a day, day after day after day.

With no good method to kill ticks, the scientists' work is aimed at considering all the ways the pests are hurting moose, and seeing if there are possible interventions by looking at the big animals' movements on the landscape, finding how many newborns survive until adulthood, and checking on their habitat.

"To see firsthand an animal that died from having tens of thousands of ticks on it, it's very depressing, honestly," Fortin said. "In the spring, when those ticks all take a blood meal at roughly the same time, most of that calf's blood is on the outside — which is not conducive to survival."

NECN recently tagged along with a team in Bloomfield, in Vermont's rural Northeast Kingdom, using radio technology to try to track a few moose.

In earlier work, scientists sedated a sample of animals, then collared them with transmitters so receivers could pick up a trail.

Despite that high-tech help, moose are notoriously elusive. None were spotted up-close on our trip, but we did find footprints, hair, and a bed where a sleeping moose smooshed ticks on its own body — leaving blood.

In 2019, some 70% of young moose in the study had died before they were a year old, Fortin said. Previous years saw deaths closer to half the animals in the study.

"It's a pretty high level of mortality," observed Jed Murdoch, a wildlife biologist at the University of Vermont. "There are ways we may manage the forest ecosystem differently that might reduce the spread of ticks across the landscape. And these sorts of things can help offset or overcome the trade-off that comes from the damaging effects of climate change."

Climate is a major factor in all this, because shorter winters are seen as good for the kind of tick that feasts on moose.

The most reliable weather data from Vermont comes from Burlington. NECN meteorologist Michael Page went back through 50 years of records, to the winter of 1969 into 1970, when Burlington's average temperature was 13 degrees.

Page found that in the decades that followed, winter averages rose and fell, but they never dipped back down to that 13-degree level. Today, winter averages in the city are nearly 7 degrees warmer than they were a half-century ago, Page found.

Josh Blouin, who's both on the research team and a nature photographer who shared several of the still images used in NECN's broadcast report, said a critical impact from those winter ticks and all their blood-sucking is on how many babies Vermont's moose seem to be having.

"It used to be commonplace to see a moose with two calves, and now that just doesn't happen too often," Blouin said.

This may sound counterintuitive, but there's a new proposal to help the animals by hunting them.

The Vermont Fish & Wildlife Department believes a limited moose hunt this fall in the northeast corner of Vermont would thin the herd a bit — making for fewer available hosts for ticks. In turn, that would cut the number of parasites in the woods, Fish & Wildlife predicts.

In a series of upcoming hearings, the Fish & Wildlife Department will both gather observations and opinions about deer and the fall hunting season, and also present information about the proposed moose hunt.

The hearings are scheduled for 6 p.m. to 9 p.m. at the following locations:

  • Thursday, March 19 – on deer and moose, at St. Johnsbury Academy
  • Monday, March 23 – on deer and moose, at Middlebury Union Middle School
  • Tuesday, March 24 – on deer and moose, at Williamstown Middle High School
  • Thursday, March 26 – on deer, at Putney Central School

Fortin said Vermont's estimated statewide moose population is 1,700-1,900.

That figure is down from more than 5,000 in the early 2000s, when biologists said that large number of animals were damaging wildlife habitats and impacting forestry practices. Additionally, the moose were becoming involved in dangerous or deadly vehicle crashes.

The population number was drawn down primarily through issuing moose hunting permits. The proposed hunt for 2020 would be limited to taking about 33 moose, Fish & Wildlife said.

An additional way of reducing population density could be to ensure moose can spread out and move easily in search of food, added Heather Furman, the Vermont state director of The Nature Conservancy.

"This is really the southern end of the moose's range," Furman observed, adding that she wants to see corridors of open land protected to give moose more terrain — especially if climate change forces their range north.

"It's hard to see a species struggling," Furman told NECN. "But in the big picture, the species is going to persist if we can maintain a connected and resilient landscape, and provide pathways for species to move."

Federal grants will support the study for a few more years, the researchers said.

Their hope is moose will remain a visible part of Vermont's ecosystem for much, much longer, if their health can get a boost in the face of the tiny, yet terrible threat from winter ticks.

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