March 17, 2010

Researchers collect data to track health of, threats to Canada lynx

JOHN RICHARDSON

— By

click image to enlarge

STAFF PHOTO BY JACK MILTON -- Thursday, February 25, 1999 -- A lynx stares through its cage at the Maine Wildlife Park in Gray.

Staff Writer

The fresh carpet of snow that fell on the forests of western Maine last week meant Mark Martin and Nick Fortin were back in business.

They steered their snowmobiles over unplowed logging roads west of Rangeley Lake, scanning the new powder for tracks left by the snowshoe-like paws of Canada lynx.

''Lynx (tracks) are unmistakable,'' Martin said. ''They're huge. They're anywhere from 3.5 inches to upwards of 5 inches in diameter.''

Martin and Fortin are lynx trackers -- part of a small community of state and university researchers trying to solve the mysteries of one of Maine's most elusive and controversial wild animals.

The cats, federally classified as a threatened species, are at the center of a legal battle over how to protect their habitat in Maine, the only Eastern state with a breeding population. The formal filing last week of a federal proposal to designate the northern one-third of Maine as protected habitat is sure to intensify the struggle between timber companies and developers on one side and wildlife conservationists on the other.

But behind the scenes, researchers are working to understand what's happening in the Maine woods. Are lynx spreading into new areas in western Maine? Is the population on the verge of decline or collapse? And does the end of large-scale clear-cutting in Maine forests pose a long-term threat to their future here?

Martin and Fortin work for the Maine Department of Inland Fisheries and Wildlife and are nearly done with a five-year effort to track lynx across their entire range in the state. When the conditions are right, they can cover an entire 36-square-mile township in a single day, measuring and photographing tracks and recording the age and conditions of the forest where lynx are found.

''We just found a lynx northwest of Rangeley, which kind of surprised me,'' Martin said in a recent interview. ''We hadn't found lynx there before.''

Finding tracks further south and west than expected is not necessarily good news for the cats. It may be a sign that they are roaming because they're hungry and the population is in distress.

Lynx themselves are harder to see than their footprints, and Martin has been on their trail for two winters without a sighting. ''I've missed them by as little as 15 minutes,'' he said.

The survey is part of a larger research effort by the state agency, which spends about $200,000 a year -- most of it grant money -- on lynx research. The department also has a team of six researchers stationed in Clayton Lake, a remote outpost in western Aroostook County.

Each winter, they trap lynx and place GPS collars on them to monitor their movements. In June, they'll use the collars to find dens and count kittens.

The Clayton Lake team has monitored about eight adult females each winter, and nearly all of them used to have kittens by summer. In the last two years, however, only one or two of the female lynx have had kittens. It's one more potential sign that the population is in distress.

The collars also allow the researchers to recover dead lynx so they can be examined in a lab. That has led to the surprising discovery that Maine lynx are being hunted by an unlikely natural predator -- fishers.

Fishers are a particularly vicious member of the weasel family. They weigh 20 pounds or less and can't run very well in snow but have killed 25-pound adult lynx in deep snow and then dragged them under trees to feed.

''They're all killed, usually by the neck, and there's no fight as well as we can tell,'' said Jennifer Vashon, a lynx biologist with the Maine Department of Inland Fisheries and Wildlife. It's unknown how the fishers manage the feat, she said. ''There are a million theories. I think, in a snowstorm, the lynx are hunkered down and the fisher is in a tree above them and attacks.''

Other reasons lynx are dying are less dramatic but may be more cause for concern. Parasites and road kills at the edge of their habitat are more potential signs of hunger and stress in the population.

Perhaps the biggest cause for concern about the lynx is a decline of at least 50 percent in the state's snowshoe hare population during the past two years. Lynx will eat other prey, such as squirrels, but their primary diet is rabbit.

In Canada, hare populations tend to crash every 10 years as part of a predictable natural cycle. Lynx populations tend to decline soon after.

That 10-year cycle may explain the hare decline in Maine. But some also believe lack of snow cover in recent winters -- unlike this one -- left snowshoe hares without their camouflage and made them more vulnerable to predators. Hares turn from brown to white in December, and brown again in April.

''We're all waiting to see what the hares have done this winter,'' said Mark McCollough, an endangered species biologist with the U.S. Fish and Wildlife Service in Old Town.

One of the most urgent questions facing researchers is how much the rabbit population can drop before the lynx population collapses.

''A lot of people are getting really concerned,'' Vashon said, predicting that some answers will become apparent in the next year.

Several researchers at the University of Maine, meanwhile, are using the state's findings to look at a longer-term concern -- clear-cutting.

Maine restricted clear-cuts in 1990 in reaction to the extensive logging in the 1970s and '80s. While the clear-cutting is credited with creating the state's rich habitat for hare and lynx, the more selective logging done today does not generate the same thick undergrowth.

Now, university scientists are using satellite images of Maine's forest, together with tracking data, to figure out if modern logging practices pose a long-term threat to the cats' habitat.

''Should we be going back and doing some clear-cuts in some areas specifically for lynx or other species?'' McCollough asked.

Martin and Fortin, meanwhile, are waiting for the next fresh snowfall in western Maine to go back to work and try to fill in their piece of the puzzle.

''It adds a sense of urgency that a lot of large-scale decisions are going to be based on what we find out here,'' Martin said.

Staff Writer John Richardson can be contacted at 791-6324 or at:

jrichardson@pressherald.com

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