90% Of Maine Moose Calves Tracked Last Year Died From Winter Tick Infestation (Yes, Global Warming)
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Of the 70 moose calves that DIF&W collared in a remote wildlife management district spanning parts of Piscataquis and Somerset counties last winter, 60 of them had died by the beginning of May. That’s 86% — a record high mortality rate since DIF&W began the tracking survey. “That’s how detrimental these ticks are,” Kantar said. “And it is pretty incredible.”
The surge has been apparently driven by a combination of a warming climate and — at least in parts of Maine and New Hampshire — moose populations that are so dense that it’s easy for larval ticks to find a host. “Those populations up there are really high density,” said Alexej Siren, a postdoctoral researcher at the University of Vermont, said of the prime moose habitat that extends from northern New Hampshire across north-central Maine to parts of Piscataquis counties. “It’s on a very different scale than other areas of New England as far as other moose habitat that’s out there.”
Unlike deer and dog ticks, winter ticks literally hunt in packs. Larvae gather in interlocking clumps on vegetation, and when one tick snags a passing victim, hundreds or thousands tag along for the ride. A solid coating of snow or a sustained cold snap kill those larvae and stop the hunt, which scientists call “questing.” But snow has been arriving later in the fall across northern New England. “The winters have shortened and the falls are longer, which means longer time for those ticks to quest and actively seek their host, which means (moose) have accumulated much more on them,” said Siren, who has worked closely with Kantar and his counterparts in New Hampshire.
“Core moose habitat in New Hampshire is the White Mountains and north, and winter ticks are still the largest factor influencing that population,” said Henry Jones, the lead moose biologist with New Hampshire’s Fish & Game Department. Areas of southern New Hampshire and Maine have fewer winter ticks because development limits moose populations. But in the vast commercial forests up north, massive clearcutting decades ago combined with regular harvesting since has created prime moose habitat.
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https://www.wbur.org/news/2022/05/18/moose-tick-deaths-climate-change