Yukon Flats National Wildlife Refuge — Late March, 2019
Just a few miles south of the Arctic Circle, a lone silver CD dangles from a willow branch and twists in the March breeze. Sunlight flashes off the surface like a signal mirror, an unsubtle invitation to the nearby open door of a large walk-in lynx trap.
Canada lynx are notoriously elusive creatures. Their grey and gold dappled fur blends in perfectly with the northern boreal forest. They are the perfect winter predator, silently and efficiently tracking prey while balancing on top of deep snow using their enormous, webbed paws. They watch for any movement with the light golden eyes and precise vertical pupils of a small ambush hunter. Like any cat, they are incredibly curious — the reflecting disk is just one of several lures a research team has set to attract their attention.
Wildlife biologist Mark Bertram and his team count on the curiosity of cats to live-trap lynx at the Yukon Flats National Wildlife Refuge just north of Fairbanks. They operate one of five study sites that span an enormous area of interior Alaska, hoping to learn more about the mysterious movements of an animal some have dubbed “the ghost cat.” Lynx can travel hundreds of miles, traversing wild country for reasons known only to themselves. “It’s really hard to know why they disperse,” Bertram says, “ We had one cat on the Yukon Flats that traveled west to east in nearly a straight line, covering 450 miles into Canada over two months. We have no idea why.”
What motivates a lynx? We have so many questions, but one motivation is clear: snowshoe hare. Canada lynx pursue an almost exclusive diet of hare, chasing them obsessively over drifts of snow and through dense forest cover. Their hind feet mimic the feet of a snowshoe hare, and they can dart and leap 10 foot spans in pursuit of their swift prey. For lynx in Alaska, snowshoe hare banquets are boom and bust over a roughly ten-year cycle as the hare population increases and then crashes back down. Does the lynx population also crash, Bertram wonders, or do they move to areas where the hare are in a different part of their cycle. If they do move, are there significant routes or patterns to their movements?
Answering these questions can help biologists understand what lynx need to survive, and possibly identify important travel corridors between the large areas of public land that make up the immense landscape-scale study. Initiated in 2014 at Tetlin National Wildlife Refuge near the border of Canada, the Lynx Project has since expanded west and north to encompass three other national wildlife refuges: Yukon Flats, Kanuti, and Koyukuk, as well as Gates of the Arctic National Park.
“Its precedent setting. I think we’re going to learn things about lynx that we’ve never learned before,” Bertram speculates. “There’s never been a regional type of lynx study across the landscape like this, it’s never been done before.” During the breeding season of early spring, the five different teams capture and collar about 60 different lynx each year. By the end of the study, they will have amassed a large and intricate mosaic of information about lynx survival and behavior. Some of this information, Bertram believes, can be very useful to land managers as they develop and plan activities on public lands.
In the frosty pre-dawn light, Bertram slips on a green aviation-style headset and begins to turn knobs and flip switches on a signal receiver box that connects to a long antenna outside of the cabin. He goes through frequencies assigned to about 30 different trap monitors, listening carefully until he reaches one that transmits a different pattern of beeps: a trap has closed in the night, possibly with a lynx inside.
Excitement fills the cramped cabin, and we suit up to spend the next several hours in the Arctic elements: layers of wool and down, neck wraps, hand warmers, bulky gloves and “bunny boots” — the infamous insulating boot of the north, found in Army surplus stores and the only way to keep feet from freezing when the temperature drops below -40 degrees. Bertram grabs his collaring kit and we climb on our snowmachines to head out and see if we have caught a cat.
As we weave our way down to the track along the river, we pass other open traps. Their white PVC frame and chickenwire walls barely stand out against the snow and brush. Instead, an inquisitive cat would probably notice the nearby shimmer of a CD or the movement of grouse wing fluttering from a branch. These visual lures work in the same way as a play lure for house cats, teasing the predator’s keen vision and bringing it closer to the trap. As the lynx approaches, its sensitive nose will pick up the musky perfume of beaver or wildcat, a scent lure that gets smeared on the bait of grouse or hare at the back of the trap.
“They come in and inspect things. We put up trail cameras at many of our traps just to watch them, and they’re very wary, they come in slowly and they’re checking everything out,” Bertram says. In the end, the lynx’s curiosity may be strong enough to lead it into the trap, triggering the door to close and setting off a different radio signal that lets Bertram know a trap is active.
We slow our snowmachines as we approach the trap that has just sent us an active signal. Bertram is the first on the scene, quickly dropping to his knees in front of a growling female lynx. “In order to study lynx and their movements, you have to capture them, you have to outfit them with a radio collar,” he explains as he opens up his bag to prepare a sedative injection.
Moving to the rear of the trap as another team member guides the cat backwards, Bertram readies the jab stick with the dosage of Telazol — a drug commonly used for sedating wildlife. His moves are well practiced: a swift angle downwards through the wire cage into the cat’s flank and the injection is complete. He steps back and crouches down to wait for the few minutes it takes as the lynx settles and nods her head into a quiet sleep.
Once the cat is sedated, the team works quickly to attach a GPS satellite collar and a numbered ear tag, take measurements and fur samples from the lynx, and collect information about her health. Bertram then gently lifts her head to an upright position propped against the insulated holding bag, and waits for the lynx to wake up.
Groggy at first, cat #016 eventually finds her footing and begins to move across the snow towards the forest. Back at the cabin, Bertram remotely switches on the collar to begin transmitting a location signal every 4 hours. For the next year and a half, the research team will follow her movements and discover whether she stays within a small home range or wanders far beyond the refuge boundary. They’ll continue to add more lynx to the study over the next few years as the snowshoe hare cycle pivots towards decline, collecting thousands of location points across the cats’ range as they respond to changing prey populations.
The Lynx Project is a collaboration between the U.S. Fish and Wildlife Service, the University of Alaska Fairbanks, and the National Park Service. Follow photos from the project on Instagram @thelynxproject.
Photos and story by Lisa Hupp, Outreach Specialist.
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