Remnants of Winter

A month ago, on the 29th of May, I spent a day collecting the thirteen motion-activated cameras that we deployed on wolverine snow-holes this spring, not knowing anything about the photos taken in our absence. Across the tundra, most of the snow was gone, patches remaining only in drainages and cut banks where it had drifted during the winter.

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Helen Chmura uses a radio tracker near the Colville River to locate collared wolverines. Photo Tom Glass.

In keeping with what we know about wolverines, most (though not all) of the sites where they had created holes still had some snow, where we found evidence of how they had used the area. It is the relationship between wolverines and spring snow that drives many of our research questions.

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A snow filled drainage as we approached the study area. Photo Tom Glass.

Upon reviewing the photos from the cameras, we discovered that five of the holes were associated with kits. At three of these, we found substantial latrines – piles of scat about a foot in diameter and several inches tall. We collected these as evidence, hoping to more fully examine their diet, and possibly to obtain a genetic sample from the kits, which would allow us to follow family relationships if we catch them again later as adults.

At many of these sites, we were also able to see the remains of the tunnels that the wolverines had excavated and used. These were extensive, sometimes stretching as much as forty feet from one end to the other. At one site we found beds, where the wolverine had apparently brought moss into the den for insulation and comfort, which were now suspended on pedestals, all other snow having melted around them.   Many sites also contained food remains, like caribou hooves, bones, and hair.

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A latrine inside a natal den (left side of frame). The sticks and debris leading away to the right likely mark the location of a tunnel. There was also a partially consumed caribou leg in this latrine. Photo Tom Glass.

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A moss bed, formerly inside a wolverine snow structure before the snow melt.Photo Tom Glass.

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Looking down a partially collapsed tunnel. Scat and bones litter then length of this section. Photo Tom Glass.

Upon approaching one site, an adult wolverine fled into a remnant tunnel in the snow. One of our primary questions is when and why wolverines leave the snow structures, so it was fascinating to observe this individual still using the site. After some deliberation, we decided to approach cautiously to retrieve the camera. When we arrived, we found two kits – both dead – on the snow near the entrance of the tunnel. A necropsy found no obvious wounds to either (though one was partially consumed), and the intact kit was severely underweight for its age. From this, our best guess is that the mother was killed (either by a predator, like a wolf, or by hunters), and the kits were left to fend for themselves. This leaves the question of the adult wolverine we observed at the hole – possibly the father, or simply another interested party. Unfortunately, our camera did not stay standing long enough to provide any evidence.

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The adult wolverine fleeing into a hole as we approached. Photo Tom Glass.

At one hole, a natal den, we captured nearly 4,000 pictures of the mother, kits, and presumed father coming and going from the area. Among these, there is a series which depicts the mother nursing the three kits, at the entrance of the den, while the male observes from a distance. In another set, the mother arrives at the den and drags in a caribou leg. In others, the kits tumble playfully around the entrance. These are fascinating windows into the lives of these creatures, about whom we know so little. In most cases, snippets like these create more questions than they answer, providing the impetus to get back out there, don the parka, and keep searching.

Written by Tom Glass, WCS research technician. June 2016.

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