Why do so many moose die in Maine?

This article was originally included on Field and flow.

It’s Maine moose side. Outside of Alaska, it has the largest population in the country of the world’s largest cervids. But Pine Tree State’s iconic animal is threatened by a far smaller creature. Since the winter, in the corner of the state with the highest concentration of moose, covering parts of Piscatakis and Somerset counties, 86 percent of the calves tracked by scientists have died. The culprit in most cases: winter ticks.

Lee Cantar, a leading moose biologist at the Maine Ministry of the Interior and Wildlife, told public radio in Maine“You look at one sheet after another of what we found in the forest of these moose, and each time it’s the same profile: it’s a winter tick.” Sixty of the 70 calves, with collars in the fall, did not survive their first. year.

Winter ticks, or moose ticks, which scientists first documented in Maine in the 1930s, hunt mostly moose. In autumn, their larvae form large intertwined groups on forest vegetation. As moose roam the woods far and wide during the autumn breeding season, the bunches cling to them. Arachnids feed on their hosts throughout the winter, dropping out in the spring to lay their eggs. The eggs hatch in the summer and the cycle begins again.

However, winter has traditionally limited the damage that winter ticks cause to moose. Early autumn snow or frost kills many larvae before finding a host. Late spring snow can also kill many eggs. However, climate change has been a boon to ticks and a curse to moose.

Alexei Siren, a postdoctoral fellow at the University of Vermont who works with Canter, said“Winters have shortened and the falls are longer, which means longer for these ticks to search and actively search for their host, which means (the moose) have accumulated much more on them.”

Some moose end in invasions of more than 100,000 ticks. A century ago, Maine moose populations declined, mostly due to overhunting, to about 2,000. But conservation efforts have since restored the official number of state animals to more than 70,000. Maine carefully manages its moose using helicopters to locate them. and oshiy, and establishes different hunting rules in 21 different areas. The state’s moose population remains stable, but this year’s worst calf deaths, combined with deteriorating reproduction rates, are a worrying trend.