State Updates Multi-Year Moose Study

People / Aug. 10, 2017 11:33am EDT

The Vermont Fish & Wildlife Department recently completed the first field season in a multi-year study to better understand the state’s moose herd. Beginning in January 2017, researchers placed radio collars on 60 wild moose and began tracking their movements.

Moose across the Northeast are increasingly under stress from a parasite known as winter ticks. The ticks are becoming more prolific as spring and fall weather has warmed in recent years, causing some moose to collapse from blood loss or die from hypothermia after rubbing their insulating hair off in an attempt to rid themselves of the parasite.

Department staff began tracking the moose using the GPS collars, visiting moose directly in the field, and examining moose that have died during the study period to attempt to determine cause of death. Staff have also been observing whether female moose are successfully reproducing and how well newborn calves are surviving their first few months.

Eighteen out of the 30 radio-collared calves survived their first winter and spring. The 12 calves that died were examined and showed signs of winter tick infestation and were generally severely underweight.

Adult cow moose expectedly fared better, with 27 out of 30 moose surviving the winter and spring period. Fifteen of the 30 adult cow moose produced calves this spring, of which 10 have survived thus far.

“We’re still very early on in this study, so it’s too soon to draw any conclusions from these data so far,” said Cedric Alexander, F&W’s lead moose biologist. “We’re pleased that we were able to successfully radio-collar the desired number of moose and that most of the cows have survived thus far.”

F&W staff plan to capture an additional 35 moose in January 2018. Vermont is the fourth northeastern state to partake in such a study.

“Moose face a variety of potential threats in the northeast, from warmer temperatures to dramatically increased parasite loads and habitat fragmentation,” said Alexander.

“It is important that we understand how much these factors are affecting our moose population in Vermont.”

Vermont’s moose herd has decreased from an estimated high of over 5,000 individuals in the state in the early 2000s to roughly 2,000 today. The majority of the reduction in the number of moose was a deliberate effort by biologists to bring the herd into better balance with available habitat at a time they were considered overabundant. A single moose can eat over 25 pounds of food a day and their browsing was damaging forest ecosystems.

According to Alexander, this deliberate reduction in the herd through hunting may have also helped Vermont’s moose stave off the worst effects of winter ticks as they have increasingly become a problem in recent years. “Winter ticks spread more rapidly when moose are overabundant,” said Alexander.

The study will run through 2019. For more information, visit the F&W website.

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