tracking

Fisher and Other Trails

/ Mike Fitz / 2 Comments

Compared to summer, winter can seem like a dull companion, especially in my corner of the globe. The buzzing of insects ceased months ago. The forest floor rests under one to three feet of snow. Trees, shrubs, invertebrates, amphibians, and fungi lie dormant. Ice insulates wetlands that were vibrating with life not long ago. Migrating birds vanished months ago. Then, there’s the dangers posed by cold weather. Numbed toes and fingers aren’t pleasant, nor are the perpetual threats of frostbite and hypothermia. All-in-all, I could convince myself that winter is a season to be endured rather than embraced. This would be a mistake, though. 

While I miss the sheer volume of aliveness that accompanies summertime, winter has many endearing qualities. It helps me appreciate the abundance of summer. Off-trail travel is often easier when wetlands are frozen and snow smooths the terrain. And few experiences are as peaceful as the immense quiet that accompanies a snowstorm in an isolated grove of trees.

But this post isn’t about falling snow. Rather, it’s about a story written in the snow. Instead of looking at the wintertime forest as lonesome and empty, snow allows me to better understand how the landscape is a fully inhabited place. 

Last Monday, I highlighted the travels of a fisher during More to Explore, a bi-weekly highlight show on explore.org cohosted by Brian Byrd and me.

In the interest of brevity for the show, I skipped some details of the fisher’s trail. Tracking is an art that I’m still learning and I argue that I’m a slow study, but a few clues revealed I was looking at a fisher’s trail rather than a fox, coyote, marten, or lynx, all of whom inhabit the area.

  • Claw marks registered in most of the prints that I examined carefully, effectively ruling out felines since their claws are retractable and don’t register reliably in tracks.
  • The clearest tracks had five toes—an important clue that rules out the canines such as foxes and coyotes. Porcupines, bears, skunks, hares, and rodents can make five-toed tracks too, but they have other features that make them distinctive.*
  • The tracks’ size were too large for other members of the weasel family who live here such as short- and long-tailed weasels, mink, and marten. I could rule out river otters too since there was no evidence that the animal slid across the snow (something otters routinely do) or sought liquid water. The trackway crossed a beaver-created swamp but the tracks did not lead to water as an otter would have.
  • The animal’s gait was a mostly loping in a 3 x 4 pattern, which is a common way for fishers to travel. The 3 x 4 lope is a method of travel where a fisher places a front and rear foot from one side of the body in the same place, while the feet on the other side do not overlap. This gives the impression of only three tracks instead of four. Fishers walk, lope in a 2 x 2 pattern, and gallop too, but in my experience they’ll use a 3 x 4 pattern much more often in firm snow than American martens.
A set of fisher tracks in the snow. Four tracks are visible. The fisher moved from left to right. The yellow notebook at bottom center is ~17 cm wide.
A clear set of fisher prints. Her five toes are perhaps easiest to see in the second track from left. Also note that the fisher created four prints here so she slightly deviated from her typical 3 x 4 lope.

A fisher trackway in snow. The yellow notebook at bottom left is ~17 cm wide. The fisher moves mostly in a 3 x 4 lope. It was headed from left to right in the photo. The tracks are shallow, maybe only a centimeter deep.
A trackway from the fisher. She was moving with a 3 x 4 lope across firm snow. My notebook is about 17 cm wide for scale.

Several other mammals were active that day as well. Snowshoe hares, red fox, red squirrels, mice, and voles all left tracks or scat to reveal their presence. I was only lucky enough to be chastised by a couple of squirrels and didn’t see any other mammals for the majority of the day but walking slowly and quietly gives one the opportunity to be surprised. In a moment of quiet contemplation, the kind you experience while gazing through trees pondering your next move, a glimmer of movement appeared in the corner of my eye. I turned my head to find a weasel bounding through the snow. I didn’t dare reach for my camera knowing I’d spook it into hiding, although I remember clearly my confusion upon seeing it. 

A long-tailed weasel changes its fur color from summer brown to winter white and back again with the seasons. In winter, they are nearly pure white except for the tip of their tail, which is black—a feature that seems to misdirect attacking predators away from the head. This weasel, however, appeared to have a dark tail and head. 

My brain needed to register a few more bounds by the weasel to clear the confusion. it wasn’t oddly colored. The weasel was carrying a vole or mouse in his mouth. As he disappeared in a thicket, I was offered a special opportunity to examine its prints for clues about that may help me better understand how small weasels move in snow when they are burdened by the weight of their prey. 

Long-tailed weasels and the smaller short-tailed weasel (ermine) travel most often in snow by using a 2 x 2 lope. When you see them traveling in this way, it looks almost like a long hop, with the front feet hitting the ground first. The front feet quickly lift into the air while the hind feet land in the same place. The weasel I watched used this method and he seemed to carry his rodent cargo with ease—an impressive display of relative strength. His prey, though, left an important clue. Each of the weasel’s bounds were accompanied by a slash in the snow, which must have been created by part of the dead rodent (a foot? a tail?) dragging in the snow with each leap of the weasel.

A single set of long-tailed weasel tracks. They make a single depression in snow in the center of the photo. A light slash is visible beneath the weasel prints. The width of the yellow notebook at bottom is about 15 cm.
A long-tailed weasel’s prints are underscored by a slash in the snow created by the rodent prey it carried.

Two sets of long-tailed weasel tracks. Each set makes a single depression in snow. A light slash is visible beneath the weasel prints. The width of the yellow notebook at bottom is about 17 cm.
Two sets of prints from a long-tailed weasel. Note the repeating slash next to each track. The weasel traveled from right to left.

As I discussed in the video segment above, the life of a fisher would be far more mysterious without the record it leaves in snow. I would have no real clue how much fishers leave scent marks or climb trees without reading their trackways. Likewise, if I’d not been in the right place at the right time or been looking in a different direction I would have missed the weasel and its meal completely. Had I stumbled upon its trail with the strange, repeating mark next to each print I’m not sure I’d reason it was from the weasel’s prey. But now, I’ll be looking for other examples like it.

I hope you have the opportunity to utilize snow to learn more about your neighbors. When the snow pack melts in spring, I welcome the change although I must admit that forest seems a bit lonelier when I don’t know who has been visiting. 

*Mammal Tracks and Sign: A Guide to North American Species by Mark Elbroch is an invaluable resource if you want to learn more.

Trail Cam

/ Mike Fitz / 10 Comments

In February, I discovered wolverine tracks in the snow. After mentioning the tracks to a resource management specialist at North Cascades National Park, we decided to set up one of the park’s motion sensor trail cams hoping to capture photos of wolverines or any other animals that might wander by. The cam didn’t capture images of any wolverines, but it did reveal the presence of other large critters. (In this post, all photos from the trail cam are courtesy of North Cascades National Park Service Complex).

On March 20, I mounted the cam on a tree with a clear view of an unplowed, snow covered bridge over Stehekin River, surmising that the relative ease of crossing the bridge would funnel wildlife across it.

Trail cam mounted on Douglas-fir tree

After setting up the cam, the first photos capture me skiing away.

GIF of person skiing across bridge

Nothing appears on the cam until March 30 when a mountain lion waltzes by!

Mountain lion walking on snow. 2017-03-20, 9:52:47 AM, 33˚F

GIF of mountain lion walking across snow

I was surprised the mountain lion was in this habitat during late March. Many deer, the primary prey for Washington state’s cougars, inhabit the lower Stehekin River valley, but I had seen no tracks of those animals anywhere within five miles of the bridge. The four feet of snow in this location was still prohibitively deep for deer. Perhaps this was a male seeking females or simply one of the resident lions moving through its territory. I’m not sure, although I found a pair of lion tracks a couple of miles north along the Pacific Crest Trail three days afterward.

After swapping out the cam’s memory card on March 23…

hand and part of person's face in front of camera, snow in background

…I left the cam alone until April 3. When I returned I noticed some large, semi-fresh tracks post-holed across the bridge. Backtracking the animal’s movement, I found it walked right under the cam before crossing the bridge. Interestingly, the cam took many photos of an empty bridge the evening before I arrived. Something had nudged the cam, triggering it for 13 seconds according to the photos’ time stamps. One photo in the sequence is completely black as if something briefly covered the lens.

GIF of trail cam sequence. Cam is nudged by animal out of frame.

The culprit was revealed a few seconds later.

black bear walking on snow with nose to the ground. 2017-04-02, 7:24:44 PM, 36˚F

 

GIF of black bear walking across snow

Bears are extremely curious. This one found the cam and investigated it seconds before walking across the bridge. Since black bears in the northeastern corner of the North Cascades begin to emerge from hibernation in early April, it may have been fresh out of the den. On the other side of the bridge it’s tracks continued straight up the hillside disappearing into the forest.

I know these animals live here with me. I see their tracks and scat somewhat often, but I encounter the living individuals less frequently. For me, the cam provided an enjoyable, albeit brief, glimpse into their lives.

A January Bear

/ Mike Fitz / 5 Comments

It was late January, but I enjoyed nearly perfect hiking weather in Big Bend National Park. The sky was clear, the wind was calm, and the temperatures hovered in the hiking Goldilocks range (for me, that’s the low 60˚s F). I had spotted a few piles of bear scat earlier that day, but all were dry and desiccated. Then in the late afternoon, I found one particularly fresh pile of crap.

This scat was soft and pliable and hadn’t been exposed to the dry desert air for very long. (I poked it with a stick to gain a very scientific measure of its age.) Was there a bear nearby? I hoped to find out.

The previous day, I stopped in the Chisos Basin Visitor Center to purchase a book to help me search for the park’s endemic oaks. A map on the visitor center wall was marked with sticky notes identifying when and where people had spotted black bears. At least a dozen had been seen over the past two weeks. I made a mental note to watch carefully for bear sign. Maybe, just maybe, I would be lucky enough to see one for myself.

Mountain rising above pine and juniper forest

The pinyon-oak-juniper habitat near Emory Peak (center) is preferred habitat for Big Bend’s black bears.

Although I spent considerable time searching for the endemic oaks (and found at least a couple, plus some species rarely found in the U.S.), bears were never far from my mind. Backcountry campsites all had bear-resistant food storage boxes, and signs clearly informed people that bears will take your unattended pack.

metal sign. Text says, "Bear Country Do Not Leave Back Packs Unattended"

Occasionally, I’d find old piles of bear scat or a marking tree.

scratch marks on bark of tree

Black bears used this Arizona cypress (Hesperocyparis arizonica) near Boot Spring as a marking tree.

No long after I photographed the marking tree, I stumbled on the aforementioned scat. Its freshness caught my attention, but it wasn’t steaming so I couldn’t be sure if a bear was close or not. I only knew it was there earlier in the day. As I proceeded up the trail, motivated to pick up my pace and return to the campground before dark, two hikers traveling in the opposite direction told me they had just seen a bear not far from the trail. This was their first wild black bear sighting, and they spoke excitedly about their experience. I thanked them for the info and continued on, now even more alert.

The hikers said the bear was near a switchback in the trail, not far from a backcountry campsite. I slowed my pace as I approached that location, not wanting to startle the animal. A moment later, through some thick vegetation, I heard cracking branches and there it was—a black bear.

black bear ears seen through thick vegetation

My soon-to-be award winning wildlife photo of a black bear in Big Bend National Park. Move over Tom Mangelsen.

What would a bear be doing out in January? Since bears are omnivorous and eat a wide variety of food, their scat reveals a world of information about where they’ve been and what they’ve been up to. The fresh bear scat I found 10 minutes before, like the older scat on the trails, was filled with fragments of pinyon nuts and shells. Pine nuts are exceptionally nutritious, containing almost 700 calories per 100 grams. The pinyons pines in the Chisos Mountains seemed to have produced a sizable cone crop in 2016, one which helped sustain the bears into mid winter.

pile of black bear scat in grass

Pinyon pine nut shells and fragments fill this fresh pile of bear scat. I found this scat just moments before seeing an active bear.

The density of the shrubs made it difficult for me to se exactly what the actual bear was doing, but it appeared to have its nose to the ground and it wasn’t moving far. Perhaps it was still feeding on pine nuts.

pine cones on the ground

These Mexican pinyon pine (Pinus cembroides) cones still hold their fatty nuts.

Black bears in the Chisos Mountains rely heavily on habitats with pinyon, oak, juniper, and grassy talus slopes, although male bears will make more frequent use of low elevation areas. Even so, this was January 26. Shouldn’t the bear be inside a den?

Black bears in more northernly locations hibernate well before January. However, bears in Big Bend don’t typically enter their dens until late January or February, and when they do many don’t seem to fully enter hibernation. Male bears, especially, are more likely to remain active. Pregnant females in Big Bend, like other bear populations in North America, have the longest average denning period, beginning in mid to late December and ending in late April.

This winter activity isn’t unique to Big Bend’s bears. Black bears in Florida have similar winter dormancy patterns. Mild weather and the prospect of food, especially, can keep bears active for longer time spans. After all, bears are avoiding winter famine more than winter weather when they hibernate. The bear I saw probably wasn’t doing anything abnormal for a Big Bend black bear. It was just another bear doing bear things like eating and shitting in the woods.

The Other Wanderer

/ Mike Fitz / 10 Comments

Most mammals aren’t keen to reveal themselves to people, which I understand. I don’t want to be around people much of the time either. Unless I’m very lucky or very observant (sometimes it’s both), I typically don’t see the more elusive animals that inhabit the North Cascades ecosystem. Winter, however, provides an opportunity to see the animals without actually seeing them.

In winter, animal tracks in snow reveal stories I could never read otherwise. Without tracks, I would be oblivious to the presence of most animals, so on every trip outside I look for them. On a recent ski journey, I found some tracks I did not expect to see.

The day was comfortable (35˚F/2˚C) and sunny. The snow was reasonable firm. I parked Large Marge at the end of plowed section of road and skied up valley. Skiing wasn’t fast, but it wasn’t a slog either. With long sleeves, I felt overdressed in bright sun, so I paused frequently to cool down and enjoy the view.

River running through snowy forest.

Pillows of snow sat on rocks in Stehekin River downstream of High Bridge in Lake Chelan National Recreation Area.

I found High Bridge, which is the boundary between the national recreation area and the national park, buried under several feet of snow.

cabin in deep snow

The NPS cabin at High Bridge was mostly buried by snow.

outhouse buried in snow

Good thing I didn’t have to use a toilet, because this outhouse at High Bridge wasn’t accessible.

Up to this point, I had seen or heard little evidence of animals. Douglas squirrels were active because I found bracts from Douglas-fir cones scattered under a couple of trees. Red-breasted nuthatches occasionally called from the tree tops (this species is one of the most common in the Stehekin Valley in the winter; at least one of the most vocal.) There was no sign of large or even medium sized mammals.

The snowy road offered a convenient path so I followed it up valley, especially since the avalanche forecast was high and I didn’t want to risk getting caught in any slide. About a mile from High Bridge, I noticed a set of faint, but fairly large tracks in the snow.

wolverine tracks in snow next to ski pole

The set of tracks I found. What animal made them?

The tracks were fairly large, although I lacked measuring tape to get accurate measurements. My first thought was “mountain lion,” but then logic started to creep in (thanks Spock). Mountain lions eat many animals, but prey probably isn’t abundant enough in the mid to upper Stehekin River valley at this time of the year to sustain a mountain lion. I saw no deer tracks, even though deer are common in the lower valley now. Other characteristics of the tracks eliminated mountain lion as the source.

  • The tracks weren’t the right size or shape.
  • Their pattern, or gait, was a 3 x 4 lope.
  • Claws marks registered with almost every track.
  • The tracks rarely broke through the snow’s surface crust. This animal, despite its size, could float on the snow.
  • Fur marks often registered around the toes.
  • Most importantly, this animal had five toes.

This was a wolverine.

wolverine track in snow next to basket on bottom of ski pole.

This fairly distinct wolverine track clearly shows the animal’s five toes. The basket on the ski pole is 7.5 x 7 cm.

The track pattern indicated it was walking in some places, but loping most of the time.

Wolverine tracks in snow.

Wolverine tracks in snow. Each set of three, starting from the bottom, represents a one lope made by the animal.

Wolverines are the largest members of the weasel family and occupy huge home ranges. The tracks were fresh, their crispness suggested they were made early in the morning or overnight. If they had been made the day before, the warm sun would’ve obscured some of their finer details.

What might it eat in this habitat? Perhaps one of the squirrels or hares out and about.

scales from Douglas-fir cone scattered on snow

A Douglas squirrel had recently torn apart a Douglas-fir cone on this pile of snow.

Snowshoe hare tracks in snow next to ski

Snowshoe hares were also moving about the forest.

At Tumwater Bridge, the wolverine continued across right next to tracks of a marten, a smaller more arboreal member of the weasel family.

wolverine tracks (bottom) next to smaller marten tracks. Tip of ski at bottom center.

Wolverine tracks (bottom) run parallel to marten tracks.

The day was waning at this point, so I turned around and left the wolverine and its tracks behind.

Last year, a large male was trapped and radio collared at Easy Pass by the U.S. Forest Service and Washington Department of Fish and Wildlife. This is almost 20 kilometers due north of the tracks I found. Could it have been the same one?

Maybe, maybe not. Wolverines occupy huge territories and are rare in this area. I was lucky to stumble upon this set of tracks before they disappeared in overnight rain. That day, I was probably the only human in the south unit of North Cascades National Park, but I certainly wasn’t the only mammal prone to wander.

Read more about on the wolverine’s status in Washington.