This is similar to the pine bark beetle now wreaking havoc on the conifer forests of the west coast of the US and Canada: winters too short and mild to kill enough of the beetles or their eggs.
Quote:A small but dangerous parasite, the winter tick, is spreading north and west as winters become shorter and now is knocking at Alaska's border.
The winter tick, which has already devastated moose populations in New England and the upper Midwest, has been confirmed in
Canada's Yukon Territory and in the Northwest Territories, where it's infecting elk, mule deer and some moose.
"Now that they're moving farther north through Canada, north and west, they're eventually going to arrive here, if they're not here already," said Kimberlee Beckmen, wildlife veterinarian for the Alaska Department of Fish and Game. "We will be next. It's only a matter of time."
Shorter winters and likely milder winters a result of AGW, of course.
These ticks are more than a nuisance to the animals, especially calves:
Quote:The average tick load on an infested moose is 40,000, and some have been found with 90,000, said
Peter Pekins of the University of New Hampshire, one of the lead scientists studying the disastrous impacts of winter ticks on New England moose.
A load of more than 40,000 ticks will use up a calf's entire blood supply in four weeks, Pekins said. "They get anemic, they have declining weight too, and that's just the end of them," he said.
Adult moose are more likely to survive, but reproduction has been affected, with far fewer cows giving birth to twins, he said.
The life cycle of the tick allows massive numbers of tick eggs to survive winter:
Quote:The spread of winter ticks is aided by the warming climate, according to Pekins and other scientists.
Because of the timing of ticks' life events, higher temperatures, earlier springs, later winters — the pattern in a warming world — help them survive, proliferate and attach to moose.
Adults females drop off animals in the spring to lay eggs, Pekins said. For an egg-laying female tick, "Her survival is much higher if it's bare ground than if it's 2 feet of snow," he said.
The resulting larvae climb up vegetation and cluster together in the fall in big balls, which passing moose or deer can pick up — and they are affected by the timing of winter's arrival, Pekins said. "The first snow event is key to killing the larval ticks that are up in the vegetation," he said.
The shorter winters helps their spread:
Quote:In the Northwest Territories, tick-infected "ghost moose" were first documented in the 1980s, and cases have increased since then.
They have spread as far north as 66 degrees latitude in the territory's Sahtu region, and have also been found on caribou, according to biologists' reports. The Arctic Circle is about 66 degrees north latitude.
The North West Territories:

Showing the ticks/eggs survive the present shorter winters:
Quote:Also ominous for Alaska is the result of past research, done by Beckmen's predecessor at Fish and Game, which suggests winter ticks can survive even harsh Fairbanks temperatures.
Randall Zarnke, a former Fish and Game veterinarian, and his research partners tested some captive winter ticks, monitoring adult females and the eggs' hatch success in three Alaska locations, including Fairbanks; many test subjects survived, said the study, published in 1990.
That was 1990, AGW has powered along since then, of course.
Quote:A recent study co-authored by Beckmen analyzed ticks and found 10 different species of ticks had been retrieved from dogs, cats, people, other mammals and wild birds at 29 sites around the state between 2010 and 2016.
Some of the tick species were native, but some were not — and some nonnative species were found on dogs or humans without recent history of travel outside of Alaska, indicating those ticks have already settled in Alaska.
The brown dog tick is one nonnative species that appears to be well-established in the state, Beckmen said.
The study also included the first Alaska record of one species, Ixodes texanus, commonly called the raccoon tick, which was found on a marten.
There is also one tick-borne disease that has long been in Alaska — tularemia. People exposed to tularemia are treated with antibiotics, but those exposures do not always result in formal diagnoses reported to health authorities, Beckmen said.
Other serious tick-borne diseases have yet to be reported in Alaska.
Not so in the
European Arctic and subarctic, where tick-borne diseases are rising in a pattern correlated with increasing temperatures. https://www.adn.com/alaska-news/environment/2017/05/06/threat-of-moose-killing-t...