Exploding tick numbers threaten

http://www.washingtonpost.com/news/energy-environment/wp/2015/10/07/ghosts-haunt-the-maine-and-new-hampshire-woods-this-time-of-year/

By Darryl Fears October 7 at 9:00 AM

Right now, in the woods of Maine and New Hampshire, tens of millions of winter ticks are pouring out of eggs and climbing up stalks until they reach an ideal peak — about the height of a moose. If a moose happens by — male, female, calf … winter ticks don’t care — they climb aboard.

Other types of ticks, such as wood ticks and deer ticks, grab a bite and drop off. Winter ticks are much greedier. They hang on for the entire winter, fattening up on blood until their bloated hides resemble a watermelon. Some moose, especially small calves, develop anemia and eventually starve. In a vain attempt to dislodge ticks, adult moose scratch until the brown layer of their fur gives way to a thin grey layer underneath. They’re called Ghost Moose, because that’s how they look.

As the climate in the two states warmed over the 20th century, and the duration of summer weather increased by up to two weeks, and the snow that kills winter ticks fell less or melted faster, their populations grew, scientists say. When conditions in the states are cold, females that leap off moose in April to lay eggs fall on heavy snow pack that kill both. But more of the eggs are now surviving to hatch in fall. A single female lays 3,000 eggs the size of salt crystals.

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Quoting the Environmental Protection Agency’s Climate Change Indicator in the United States, Stampone said some locations in the Northeast are seeing a reduction in precipitation falling as snow. “We’re getting precipitation but more of it is falling as liquid,” she said. There is wide variation from year to year, she said, but in general, there are “fewer days and less depth of snow on the ground.” Maine’s weather stations track snow depth and measurable snow pack is recorded on fewer days. “Maybe there’s less snowfall or it was warmer and more snow melted,” Stampone said.

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Winter ticks aren’t individually scattered over the bodies of their hosts. They feed in big groups, like clumps of grapes on a sprawling vine, ballooning until an animal that was the size of a speck is as big as a cough drop. Moose become so stressed from hundreds of thousands of tiny bites every minute and every day that they can’t eat even if food is handed to them.

“They look terrible. Their body weights are down. They have secondary skin infections from multiple bites,” Kristine Rines, a New Hampshire moose biologist said when the study started two years ago. They lose so much fur that they freeze whenever the weather manages to turn cold.

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“In the central and White Mountain portion of the state where winters are short, we’ve seen a steady decline over the past five to seven years,” Rines said. The state’s moose population is about 4,500, at least 3,000 fewer than five years ago.

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