By Dr. Matthew Scrafford, Wildlife Conservation Society Canada
Tracks left by wildlife provide a wealth of information that help inform their management and conservation. Biologists like me use them to understand what species are present in an area, their abundance, their habitat use and movement, and what they eat. Many biologists prefer to research wildlife with tracks because it is less invasive and costly than live trapping and releasing them, or luring them into the range of cameras.
Tracks might be the only evidence you see of cryptic species such as wolverine – a wily and iconic carnivore well known for its long-distance movements, toughness, rarity and association with wilderness.
Following human settlement of North America and until relatively recently, wolverines were rare in the mountainous areas of the western United States, especially in the North Cascade Mountains of Washington state. Excitingly, wolverines have recently dispersed from existing populations in the Rocky Mountains to recolonize some of their former habitat here.
Ensuring that we correctly identify wolverine tracks is critical to the conservation of wolverines in the North Cascades. To that end, the Cascades Wolverine Project (CWP) is monitoring this vulnerable population along its southern range through a community-science tracking project.
CWP’s track observation program encourages the public to submit photos and locations of possible wolverine tracks they find while hiking, skiing, snowshoeing or otherwise exploring the North Cascades. These data will then allow CWP to monitor any changes in wolverine distribution such as range extension or retraction.
But being a good tracker takes practice and patience, especially if the animal you are tracking is a wolverine! A tracker following wolverines in cold, snowy and remote regions of the northern tundra, mountain, and boreal forest – where wolverines are typically found in North America – might mistake wolverine prints in the snow for lynx, wolf or fisher tracks. These mistakes are easy to make because soft and deep snow might not register a paw pattern. Or a track may have melted in the sun, been trampled by multiple species, or become blurred by snowdrifts and be hard to recognize.
To minimize misidentification, trained trackers and biologists examine photos submitted by the public to verify if they are indeed from a wolverine. Yet even trained professionals, who are more accustomed to identifying tracks in the field than on a computer screen, can have a tough time verifying whether submitted tracks are indeed from wolverines. Therefore, we need to be able to test their ability to connect track photos to the animal that made them. But how can you ever be sure that a photographed track is from a particular species?
To address this challenge, the Wildlife Conservation Society Canada retooled its wolverine research project – primarily established to live-trap and monitor wolverines over a 6,500 square-kilometer area in northern Ontario where there is extensive forestry activity – for a new purpose.
When we release a wolverine, lynx, fisher or wolf from our live traps and follow their path, we can be confident we are looking at the tracks of a particular species. Next, we follow CWP’s track submission protocol and photograph and measure the animal’s tracks to document the various trail patterns associated with walking or running. Then we show these images to trained trackers to see if they identify the correct species. If they ace the test, we know that our current standards for submitting photos are sufficient and we can be confident in our data set. If they fail, we may need to modify what we need from our community scientists.
For example, they might need to submit additional information about the area, or the photo might need to be taken at a different angle or with better lighting. There also might need to be a recognizable object in the frame to see the scale of the paw prints. Confirming a wolverine track can hinge on such details.
We also expect our work with CWP to provide information on what characteristics of tracks are most difficult to distinguish between species and how specific snow conditions might lead to track identification error. This could lead to better training materials for our volunteers.
As community scientists, biologists and trained trackers become better able to identify wolverine tracks in the snow, we hope to collect ever more reliable data on the extent to which wolverines are living and thriving in Washington state and develop strategies to conserve them here and throughout their range.
Dr. Matthew Scrafford is an associate conservation scientist with the Wildlife Conservation Society Canada.
Photo credits: Banner | William Halliday © WCS Canada