When there is snow at sea level, it's a good time to go exploring for animal tracks and signs, and the area between the Back Loop and the Mendenhall Glacier is a fine place to do it. Recent forays into this area by ski or hiking boot discovered evidence of animal activity, even though we didn't usually see the critters themselves.
Beavers had been busy in some spots, cutting cottonwood trees to obtain the smaller branches to put in their winter stashes of food under the ice. There are some huge beaver lodges on some of the ponds and along the river. Beaver dams have created ponds of several small drainages. These ponds are great for cross-country skiing when they are frozen, and they provide fine habitat for young coho salmon and dolly varden, dragonflies, ducks, and herons. Because the beaver dams have backed up water over some of the hiking trails, a group of concerned citizens is working to find ways of keeping the trails accessible to human joggers, strollers, and dog-walkers, while simultaneously maintaining the beaver population. The habitat value of the beaver ponds is great, as are the educational opportunities provided for visitors and residents alike. So this citizen group is looking for a win-win solution to the problems caused by beaver ponds that extend over the trail-ways to keep the beavers and the trails.
Snowshoe hares have left their distinctive tracks through the brush, the huge hind feet making these tracks impossible to mistake for something else. Our resident black wolf sometimes makes a meal of a hare (and of unwary beavers), so the hares are seldom far from cover. The hares browse on willows and other shrubs but, judging from the bunny-height clipped stems, they seem to have a particular liking for Alaska willow.
Some of the frozen ponds and sloughs have occasional small openings (about a foot across) in the ice. These openings may be caused initially by tiny upwellings or springs, but they are used regularly by mink and otter that dive through the holes in search of fish. One such opening had been used so heavily that the snow was packed down all around it by the repeated impact of these four-footed hunters.
We found the trail of a wide-ranging otter that had traveled steadily across much of the Mendenhall Recreation Area. The characteristic pattern of alternating push-off by the feet, followed by a 6-8 foot slide mark, looked like a great way to get from one place to another.
The black wolf had cruised along the trails and frozen ponds. His footprints are wider than most dogs, and the line of prints is quite straight (dogs commonly have some prints offset from the others).
In one place we saw tracks that could be those of a wandering pine marten, although this is not their favored habitat. Marten tracks are bigger than mink tracks, even though the body sizes are similar. Tiny tracks, showing a thin tail-drag mark, of deer mouse or long-tailed vole were rare, but they made a beautiful tracery in the snow. In soft snow, a shrew leaves a narrow groove just the width of its wee body, and the groove usually ends in a very small hole down into the snow. In one spot we found the hopping track of a small bird, probably a junco.
Still other tracks may be seen in this area. Porcupines huddle in the spruce trees, munching the needles, and leave their waddling track of short steps and tail-scrape behind them in the snow. Herons leave splayed, long-toed prints beside the few spots of open water. Ravens march across the snow, making a narrow print that is wider toward the front. Ptarmigan come down from their mountain haunts to eat buds and seeds, and occasionally their well-feathered tracks are found among the bushes. The mountain goats from McGinnis and Bullard sometimes hang out by Nugget Falls and upon occasion their tracks are even seen down on the flat areas.
We haven't seen many actual live critters, despite all the evidence of their presence. But a big flock of pine siskins, maybe mixed with redpolls, went twittering by. A couple of magpies squawked overhead, flying high over the trees. Eagles sometimes perch along the river, in hopes of an absent-minded duck or a fish.
What a fantastic "backyard" we have here in Mendenhall Valley! Not a totally domesticated park, but easy access to plenty of wild things to see. Juneau folks are very lucky.
* Mary F. Willson is a retired professor of ecology and a Trail Mix board member.