Known for their long, black ear tufts and ability to hunt ghostlike across the surface of deep snow, Canada lynx are the elusive, midsize cats (hardly bigger than a large house cat) that feed almost exclusively on snowshoe hares. Historically, this boreal forest predator’s habitat extended from Alaska and Canada south into much of the northern United States.
Although Canada lynx were never abundant in the U.S., they probably did occur in most northern states and western mountainous areas as far south as Colorado. Today, however, in the Lower 48, the cat exists only in several small, disjunct populations in Colorado, Idaho, Maine, Minnesota, Montana and Washington.
At least, that’s what we thought.
Room up high
Recently, researchers from Washington State University (WSU) undertook the first occupancy survey for Canada lynx in Glacier National Park. In the past, most investigations into the cats’ population numbers happened in the winter when it’s possible to use bait to lure the animals to live traps. But Glacier is a difficult place in which to conduct wintertime surveys: the roads are not maintained, and the use of snowmobiles isn’t feasible. According to the National Park Service, snowmobiles are not permitted anywhere within the park’s boundaries. So, compared to other areas which are surveyed for Canada lynx, Glacier National Park is extremely difficult to access.
To address these challenges, the WSU researchers decided to see if a camera-trapping method they had previously tested in Washington could be used to determine the presence and density of Canada lynx in Glacier National Park over the summers of 2018 to 2021.
For the first part of this study, which was published in the Journal of Wildlife Management on February 25, 2023, WSU scientists in conjunction with National Park Service scientists set up an array of 300 motion-sensitive cameras about half a mile apart on hiking trails across much of Glacier, including remote, backcountry areas. Surprisingly, what they discovered is that the park is home to around 50 Canada lynx, which is much more than they expected.
The results also revealed that the Canada lynx are distributed not only across most of the 1,600-square-mile Glacier National Park but also at lower elevations, which could prove extremely helpful to the cats as the climate continues to warm. Canada lynx are a cold-adapted species that needs deep snow. Since the main question regarding the lynx’s continued survival is climate change, we now know that, in Glacier at least, they have a lot of room to move up in elevation as the world warms.
Markings down below
For the second part of the study, the scientists set out to determine Canada lynx density in specific areas of the park by identifying individuals based on distinctive coat attributes. Compared to other cats, lynx have subtle markings that appear only on the inside of their front legs. So, the researchers set up cameras on either side of trails to attempt to get pictures of such markings that then could be used to identify individual cats in an area.
Despite the difficulties of image blur, poor lighting, vegetation and other factors, the researchers were able to link approximately 75 percent of the lynx they photographed to specific individuals. They then combined the results of the park-wide occupancy survey with their density analysis to extrapolate an overall population estimate for Glacier National Park of about 1.28 lynx per 38 square miles of terrain.
Numbers on a baseline
The WSU researchers say that they hope their survey will provide a baseline population estimate to help their collaborators in the National Park Service to keep tabs on the numbers of Canada lynx in Glacier. They are also continuing to use the methods they perfected in the park to determine the size of lynx populations in other locations. Currently, they are leading a long-term effort to survey populations of the cats in the state of Washington, one of the most threatened habitats for Canada lynx in the U.S.
I think that the methodological contributions of this study are almost as exciting as the surprising results. They give researchers a better way to count individual lynx, which is important for understanding how to keep the cats’ populations strong. The U.S. Fish and Wildlife Service is currently charged with developing a recovery plan for Canada lynx, so the more information they have on their status in places such as Glacier National Park, the more help we can all give them.
Glacier National Park is already an astoundingly beautiful place; but to my mind, knowing that the park could be a much-needed climate refuge for Canada lynx in the future makes it absolutely breathtaking.
Here’s to finding your true places and natural habitats,