The magic of wolverine tracking
North Cascades Highway is nearly open. The snowmobiles are put away, the traps are closed for the season and the wolverine crew has moved on to other endeavors. A few camera stations wait to be collectedâ€”hopefully holding a few late-season wolverine pictures on the memory cards. Yet there is one last aspect of the 2010 season that we all wait on.
Somewhere on a shelf in the office are vials with dates and GPS coordinates carefully recorded. Inside is blue desiccant and wolverine hair. In a drying box outside the office door is a collection of wolverine scat. This is the culmination of yet another aspect of the wolverine study in the North Cascadesâ€”following wolverine tracks to collect hair and scat.
To this end, members of the crew took several trips into the backcountry in search of the elusive wolverine. Multi-night trips. Backcountry skis and sunblock. Other people do this sort of thing for fun, but this was for science. Someone had to do it, right? In our defense, it is a bit of work. Heavy packs and cold nights. And a lot of GPS work. Everything had to be recordedâ€”the exact route followed, any tracks encountered, and a plethora of details of weather and snow conditions. Not your usual backcountry trip in search of slopes of deep powder. A scientific expedition in search of wolverine tracks. But hopefully a few good turns in the process.
(Title) In search of wolverine tracks on the east side of the Pasayten Wilderness (Above)Â Brandon and AdamÂ begin their search on the way to Sawtooth Crest
Why, you ask?
Think about the North Cascades. High, rugged mountains. Few roads. Even in the summer it takes a bit of effort to get back into the heart of the country. In winter it is even more difficult. Recent modeling of wolverine denning sites has shown that a major factor of wolverine habitat is areas that hold snow cover late into the spring and summer. Applying computer modeling to the North Cascades, we get a map of likely wolverine habitat that highlights areas over 6,000 feet or so. Tough areas to get to. At best, with our traps and camera stations, we get near prime wolverine habitat, but not quite into it. We hope that we get lucky and find a travel corridor of lower habitat that the wolverines occasionally pass through. Yet we know we can not quite get up to where the wolverines really are. And it is frustrating.
In an effort to get just a little closer, and to explore the edges that do not have snowmobile access, the backcountry trips were planned and put together. By getting out of the usual routes we have followed over the last few years, we hoped to better our chances of finding wolverines that we had not otherwise trapped or photographed.
Exploring the Pasayten Wilderness in search of wolverine tracks
A set of wolverine tracks observed in the North Cascades
So whatâ€™s the big deal about finding tracks?
Well, remember the scat and hair I mentioned earlier? Â That is the ticket. The tracks are just the avenue. Tracks eventually lead to something, and in our case the real goal was to collect hair or scat. Other wolverine biologists in Montana found they could find a sample of some kind after following tracks for an average of 2.5 km or so. Does not seem too far. Except that this is a wolverine. They love steep terrain. They do not mind avalanche chutes and precipices. They regularly go places we wouldnâ€™t dare. And then there is the ever-changing tracking conditions. Wind, snow and trees conspire to obscure the best of tracks. But still, somehow it works.
The rugged terrain of the North Cascades
AnotherÂ powerful set of wolverine tracks
The beauty of the effort is not the trail in the snowâ€”though it is interesting dataâ€” and not even the hair and scat, but rather the DNA that can be pulled from the samples. When a critter takes a crap in the woodsâ€”you probably count as a critter in this contextâ€”the scat left behind contains not only evidence of what it has been eating, but also cells that have sloughed off the intestine walls in the process of the scat moving through. Magicians in a lab somewhere can tease these cells from the scat sample and glean a world of information. Sex of the individual, an individual DNA â€œfingerprint,â€ and the relation of the individual to other individuals, and to other populations, even. All of this learned from a dropping collected in the snow. Hair is much the same. The best hair has a small sample of flesh at the base, and even if there is no flesh, there is still information embedded in the hair shaft.
Such is the wonder of modern technology for the field biologist. We can ski into the backcountry, find wolverine tracks and find samples that will get us some DNA. This tells us that there was a wolverine out there. But the real magic starts in the lab, where they can get back to us and tell us exactly which wolverine it was. This can be further extrapolated to suggest how populations are related and whether a particular individual was born in the area or has arrived from somewhere else.
Magic. Sometime this summer, those samples will get packed up and sent to the lab. We will see not just that there was a wolverine out there, but exactly who it was.
Photos courtesy of Daniel Harrington.
The Author â€“ Daniel Harrington
Daniel Harrington is an itinerant wildlife biologist who has stumbled from seasonal job to seasonal job for the last fifteen years or so. He has held addresses in twelve different states, and gained experience working with raptors, songbirds, Canadian lynx, northwest amphibians, and now wolverines. In addition to a degree in biology,Â he holds a degree in English/writing, and has been published in several newspapers, the Methow Naturalist, and Oregon Literary Review. He also authorâ€™s a blog.
Studying Wolverines in the North Cascades
US Forest Service employees and volunteers from the Methow Valley Ranger District, with direction from the USFS Pacific Northwest Research Station, have been trapping wolverines in the vicinity of the Methow Valley for five years, and have gleaned valuable information from GPS collars placed on five different wolverines. Little is known about North Cascades wolverines, and they are an extremely difficult animal to study. This studyâ€”the only study of its kind in the Pacific Statesâ€”seeks to understand the size and dynamics of the wolverine population in these mountains in order to estimate the size of the population, potential threats, and any management implications. The North Cascades appear to provide an â€œislandâ€ of wolverine habitat, and historical records indicate that wolverines were extirpated from the area in the middle of the century and have only re-established a steady population in the last twenty years or so. Therefore the genetics and gene flow of this population is of particular interest. In order to expand and build upon the data already provided by trapping, this winter we begin establishing baited camera stations and snow-tracking wolverines, hoping to find and identify additional individual wolverines in the area.