10/10/2026
Of the moose calves Maine biologists tracked with GPS collars this year, 72 percent died before their first birthday. State moose biologist Lee Kantar says winter ticks are to blame.
It is not an outlier. Since monitoring began in 2014, annual losses among collared calves have ranged from 8 percent to 87 percent. So what makes a parasite this small so deadly?
Winter ticks wait on plants in the fall, latch onto a passing moose, and stay through the winter, feeding on blood. In New Hampshire, one adult can carry upward of 50,000. "Essentially, they get the life sucked out of them," said Henry Jones, the state's moose project leader. Adults often survive, thin and anemic. Calves have far less to spare.
In earlier Maine tracking, Kantar said calves weighing about 400 pounds in January had lost 25 to 30 percent of that weight by spring. But why are there so many ticks now?
Shorter snow seasons and warmer winters give the ticks more time to find a host. Jones says climate change reaches moose mainly through parasites. Crowding matters too. When moose are dense on the land, ticks have more hosts, and their numbers climb with them.
A University of New Hampshire study followed 179 radio-marked calves in New Hampshire and western Maine from 2014 through 2016. A total of 125 died, and tick infestations accounted for nearly 90 percent of those deaths. New Hampshire's herd has fallen from a late 1990s peak of 7,000 to 8,000 animals to roughly 3,000 to 4,000.
The state has responded by raising moose harvest targets in the north, hoping fewer animals will mean fewer hosts. This fall, 33 hunters hold permits, drawn from 5,914 applicants. The season runs October 17 to 25.
The pressure reaches Utah too, where officials reported 34 moose deaths in the Wasatch this spring, though not all were tied only to ticks.
By early spring, the ticks drop to the ground to lay eggs. Come fall, they will be waiting.
If fewer moose may mean healthier moose, how should wildlife managers weigh the animals lost today against the herd they hope to save?
Sources: Maine Public / New Hampshire Fish and Game / University of New Hampshire / Associated Press / New Hampshire Bulletin / TownLift
(This photo is used for illustrative purposes only.)
