Following Lynx
Tracking the elusive cats to learn their habits and habitats will inform species recovery and forest management practices

About the Photo: Angela Fuller uses radio telemetry to find lynx tracks and a global positioning system (above) to record the location of tracks and vegetation plots. She and her team strive to understand how lynx move through different types of woodlands and hunt snowshoe hare.

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Bushwhacking through the Maine woods in winter is no picnic. Snowshoes are required, but deep powder can hide downed trees and layers of ice that make the going treacherous. Moreover, snow can pile atop dense stands of small conifers, creating hard-to-see holes deep enough to swallow the unwary traveler. Short days limit the daylight hours. Temperatures are often below zero.

None of this has stopped Angela Fuller. For the last two winters, the University of Maine Ph.D. student in the Department of Wildlife Ecology and a crew of wildlife technicians have strapped on their snowshoes, packed a lunch and put monitoring equipment on their backs to track one of Maine's most elusive forest animals, the Canada lynx (Lynx canadensis). Their goal is not to observe lynx directly. (In fact, Fuller has never seen a lynx in the course of her fieldwork.) They want to understand how lynx move through different types of woodlands and what they need to hunt their favorite prey, the snowshoe hare.

The lynx is a tawny-colored wildcat, just under three feet long from tufted ears to stub tail. In the U.S. outside of Alaska and Hawaii, it is listed as threatened under the federal Endangered Species Act. The size of the American population is unknown, according to the U.S. Fish and Wildlife Service, but during colonial times in the East, lynx were reported from Pennsylvania to Quebec. Maine had a bounty on lynx that was not repealed until 1967.

Today, Maine is considered the species' southern limit, although lynx have been seen in New Hampshire. Larger populations exist in Canada and Alaska, where they are hunted for their fur. Researchers also monitor lynx in Minnesota, Montana, Idaho and Washington.

Lynx research takes Fuller and her crew into northwestern Maine, not far from the Canadian border. On a typical day, they are up well before dawn to drive 20 miles to a logging road. As the sun breaks over the horizon, they fire up snowmobiles and turn on radio telemetry equipment. They head down logging roads where they listen for the telltale beep of a nearby lynx in their receivers. Their goal is to get close to one or more of the animals that state and federal researchers have outfitted with radio collars.

Once a lynx is located, the researchers zero in not on the animal itself but on its tracks. They follow the tracks back in the direction from which the animal came, studying how forest characteristics might have influenced its movements.

"We have a general idea where the lynx are located, but they can move around a (home range) that's 20–55 square kilometers (8–21 square miles). So we're traveling on a lot of roads to figure out where it is. We want to find it as soon as possible, because then we have to walk in on snowshoes to where we pick up the tracks. And that's where we actually start our work," Fuller explains.

Angela Fuller uses radio telemetry to find lynx tracks and a global positioning system (above) to record the location of tracks and vegetation plots. She and her team strive to understand how lynx move through different types of woodlands and hunt snowshoe hare.

Photos courtesy of Angela Fuller

Her research is of interest to federal agencies that are developing a national recovery plan for lynx, and to forest landowners who are increasingly driven by environmental objectives.

"Fuller's work is a key piece of research that will help us to better understand the ecology and management of lynx in the Northeast," says Mark McCollough of the U.S. Fish and Wildlife Service, which has funded Fuller's work. McCollough, a UMaine graduate, represents the Northeast on the national committee developing the recovery plan.

Fuller has already contributed to the planning effort. Part of her UMaine master's degree research focused on the abundance of snowshoe hare in forests managed using partial harvesting methods. She found that hare are less abundant in partially harvested sites than in the dense, new growth of regenerating clearcuts. The implication, says McCollough, is that clearcutting is desirable at some level if forest managers want to provide habitat for hare and lynx.

Other organizations that conduct or support lynx research in Maine include UMaine's Cooperative Forestry Research Unit (CFRU), which provides Maine forest landowners with science-based management information. Since 1999, the Maine Department of Inland Fisheries and Wildlife has been studying lynx with a focus on habitat and population status. The Nature Conservancy and the Maine Agricultural and Forest Experiment Station also provide funding for Fuller and other scientists.

Biologists estimate that Maine's lynx population is in the hundreds and growing, although its true size is not well known. If lynx are indeed expanding their population in Maine, it may be a relatively recent phenomenon, one that could be a result of an abundance of snowshoe hare or the ways in which forest owners have been managing their lands, Fuller adds.

As a master's student, Fuller, who grew up in Colchester, Vt., worked on a landmark study of another northern forest mammal, the American marten. Marten are smaller than lynx, and their trails frequently snake under logs and downed trees.

Today, Fuller's Ph.D. project is one of several lynx research efforts advised by UMaine Professor of Wildlife Ecology Dan Harrison. Under Harrison's guidance, students are evaluating habitat relationships of lynx and snowshoe hare in the managed forests of northern Maine. Since coming to Maine in 1988, Harrison has lead a program focusing on predator-prey relationships in forest ecosystems, as well as interactions among species such as the Eastern coyote, bobcat, fox and wolf.

Fuller's winter tracking begins in January. She and her crew live for three months at a time in a logging camp owned by Clayton Lake Woodlands in Aroostook County. Their duplex cabin includes shower and kitchen facilities. "It's kind of posh compared to what I was used to on the marten project," where months were spent living in a trailer with no running water or electricity, Fuller says.

When it comes to tracking lynx, gender matters. Male lynx are typically easier to follow — and for longer stretches — because they tend to stick to trails and open areas, Fuller says. Females with kittens like patches of dense vegetation, and tracking them can mean crawling through blowdowns and thick brush.

"I have never seen a lynx when we're tracking, only ones that were trapped (as part of state and federal research studies)," she says. "Two of the technicians saw one off on a side road from the main logging road. When they heard the telemetry signal, they waited at the intersection behind some trees. The lynx came walking straight toward them. It sat, scratched itself, rolled in the road and urinated. They got to watch it for a long time. They were really excited. It ended up walking right by them."

Crew members get to the heart of Fuller's research as they work along the track, establishing small plots to survey vegetation every 325 feet. In each, they painstakingly count the trees and saplings of different species, estimate average tree height and the density of tree canopy. They also take a basal measurement of tree trunks in a cross section of the plot.

Relating vegetation to lynx behavior means thinking like a lynx. "When you're following the tracks, you have to think backward in terms of how (the lynx) was making decisions. I'm trying to figure out if lynx are selecting similar vegetation as snowshoe hare. Or are they located in areas that have high snowshoe densities?"

The crew records areas where the lynx might have stalked a hare, rested briefly or slept overnight. They note the tracks of other animals that crossed its path, as well as the twists and turns of the lynx.

Places where the lynx killed a hare get special treatment. "Sometimes it takes time to figure out where the lynx came from, where it ended up and what happened in between. How long did the chase take? Was the lynx bounding or jumping? Was it in an open area when it killed the hare and then dragged it into a more closed canopy area? I'm measuring all these things," says Fuller.

Fuller once watched from a plane as a lynx stalked a hare. "You'd think it would capture and kill immediately. But hare are very fast and more efficient than lynx at going through dense vegetation. The hare came out of the vegetation and the lynx slowly stalked it. The lynx never had a burst of speed until that final moment when it was actually going to kill. It conserves its energy until it knows it can finally reach (its prey)."

Although scientists know little about most aspects of lynx reproduction and behavior, the predator-prey relationship between lynx and snowshoe hare has been thoroughly investigated. Population cycles of the two species are closely linked. Researchers in Canada have recently suggested that if a changing climate alters the balance between lynx and hare, other changes could ripple through northern forest ecosystems.

For Fuller, the ultimate question comes down to how forest practices such as selection harvesting, clearcutting and pre-commercial thinning affect that balance.

"It's possible that forest practices have increased the number of snowshoe hare in Maine and, thus, lynx. But forest management practices change. There's no guarantee that we'll continue to manage the woods like we do now.

"What's important is long-term planning for forestry — thinking about how the landscape composition will change through time, the placement of different cuts, juxtaposition with mature forest — and how, on a landscape scale, that will affect different species."

by Nick Houtman
November-December, 2004

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