In the previous post, 'Big Creek Ice Sculptures,' I praised the creek for its artifice with snow and ice. Beyond their beauty, the creek's frozen formations tell stories about the season's weather and the creek's responses. For those of us who want to know more about our other-than-human neighbors, it doesn't get much better than exploring along creeks in winter when the ground is snow-covered and animal tracks are easier to find and identify. As riparian zones bordering creeks are rich habitats that tend to be protected from winter winds and human disturbance, they are heavily used by wildlife. So grab your mittens again, and let's head to the creek.
1 - River Otter Slide No. 1 - There's no mistaking this river otter slide in deep snow. It's not unusual to see otter sign along Big Creek, but seeing otters themselves is very rare - about 1% of walks along the creek. This otter was sliding toward the bottom of the photo, and you can see where it had to thrust with its legs to keep sliding where the land leveled out.
2 - River Otter Tracks in Snow No. 1 - River otters, like all members of the weasel family (Mustelids), have five toes on both fore and hind feet, but only four toes show in some tracks. In contrast, most other native mammals of similar size have only four toes. If toes can't be counted, Mustelid tracks can generally be identified by their wedge shape (wider in front) and their 2-by-2 bounding gait (see Photo 3).
3 - Fisher Tracks in Snow No. 1 - The 2-by-2 bounding gait and the size of these tracks suggest river otter, but the habitat (upland hardwoods) and the animal's behavior (going tree to tree) indicate it was a fisher, or possibly a marten. Grey squirrels, which build dreys (twig and leaf nests) in this northern red oak stand, were the likely prey being sought.
4 - Fisher Tracks in Snow No. 2 - Here are two of the fisher tracks from the trail shown in the previous photo. Actually, these are four tracks as the hind feet register over the front feet in the 2-by-2 bounding gait. The wedge-shaped prints are elongated where the feet dragged forward out of the deep snow.
5 - Mink Tracks in Snow No. 1 - More 2-by-2 tracks, a trail into the creek, and tail drags - another otter? Good guess, but if you were there, you could tell the tracks are too small for an otter. Must be a mink, or two (although mink are usually solitary). The identification is confirmed by the spread out toes, a common feature of mink tracks, especially on the front foot.
6 - White-tailed Deer Tracks in Snow No. 1- White-tailed deer often drag the tips of their hooves when they walk, and this habit can help determine their direction of movement when tracks are obscured, as in this deep snow. Can you tell which way this animal was moving?
7 - Snowshoe Hare Tracks in Snow No. 1 (Below Left) - Hares (Lagomorphs with precocial young) and rabbits (Lagomorphs with altricial young) are built for speed on the ground, and the track patterns of both show the distinctive triangular pattern of the hopping gait. This gait is known more precisely as the 'diagonal front feet hop' in contrast to the 'paired front feet hop' of tree-climbing species (see Photo 8). The snowshoe hare who made this track was hopping toward the top of photo on thin fresh snow over a supporting crust. Why then are the large hind feet in front? If that's confusing to you, ask a child to hop around like a bunny and examine their tracks.
8 - Red Squirrel Tracks in Snow No. 1 (Below Right) - Tree squirrels and other arboreal mammals are, not surprisingly, built for holding on tightly in the way their feet are made and in how their limbs work in opposing pairs. As these red squirrel tracks demonstrate, their body form results in a paired front feet hopping gait when they are on the ground. Like the snowshoe hare, the squirrel's hind legs swing past the front legs when hopping, resulting in a track pattern with the hind feet in front. Try visualizing your track pattern as if you were playing leap frog. I wonder if frogs do it the same way?
9 - Deer Mouse Tacks in Snow No. 1 (Below Left) - This one's kind of chaotic, but it's another good example of a tree-climbing species with a paired front feet hopping gait. Deer mouse tracks look like tiny red squirrel tracks, but the tail slaps and tiny size give it away. The UP has three species of weasels that turn white in winter, and I think one of these made the larger tracks scattered about the scene while hunting deer mice.
10 - Meadow Vole Tracks in Snow No. 1 (Below Right) - Unlike deer mice, which do indeed spend much of their time climbing shrubs and trees, meadow voles pretty much stay on (or under) the ground and get around with the walking gaits of crawling (3 feet always on the ground) or ambling (2 feet always on the ground). Such walking gaits result in two parallel rows of alternating prints, which make zipper-like patterns in snow of certain depths.
11 - Mouse Maze - I can't find 'plowing' listed as a mammalian gait, but here it is. What was this deer mouse doing - foraging for tiny seeds, making a mouse version of a snow angel, scratching a belly itch, signaling aliens? Perhaps it was just taking a break from the claustrophobia of the subnivean zone it lives in between the ground and the snow during much of the winter.
12 - Tracks in Snow Quiz No. 1 - Finally, take a crack at his one. How many species can you identify? Which way were they going? What were the snow conditions like? Imagine if you could also smell the differences among tracks!