Winter in the Northeast is such a wonderful time to be outdoors. The air is cold and crisp and enlivening. The forest canopy has cleared itself of deciduous leaves and the understory of non-woody plants which gives the forest an incredible openess especially in comparison to the dense leaf cover of our summers.
Yet my favorite aspect of winter is by far the snow. Yes, its true that not every one enjoys shoveling sidewalks and driveways, spending an extra few minutes cleaning off the car with improper footwear or without gloves in a mad rush for work. However, I couldn't give up moonlit walks made brighter by the snow covered ground or the excitement of an enormous snowstorm ushered in with thunder echoing through the hillsides. Winter is a truly special time and for naturalists a wonderful time to look for animal track and sign.
Several weeks ago I went for a walk with a friend who alerted me to some Fisher tracks he'd found a day earlier. The night before we set out there was a dusting of an inch or so on top of an already existing hard crusted snow pack providing great conditions for tracking. Enough of a substrate to allow for prints to register and not enough snow to cause animals to change their gait (walking/running pattern) to compensate for moving through deep snow.
We found fresh tracks of a male Fisher and followed its explorations for a few hours. Fisher are of the weasil family, Mustelidae, and exhibit the morhpholoy or physical charactaristics of weasels along with many behavioral patterns. One such behavior that is quite charactaristic of fisher is its curiousity. We followed its trail, laughing with its apparent indecision of direction. Its trail led us up stumps, around the bases of trees, up dead trees, down the other side. It seemed to explore everything of remote interest in the forest, changing its direction of travel 90 degrees in an instant. We left it's trail for a while and picked it up again, which led us to a large white pine inhabited by four large porcupine resting in its branches.
Fisher are generally crepuscular animals (active mainly at dawn and dusk twilights), but alter their schedules as needed. They are opportunistic hunters and incredible predators as demonstrated by their varied diet consisting of everything from mammals such as rabbit, mice, beaver kits, flying squirrels, and marten, to insects such as grasshoppers, to birds, frogs, nuts, and berries. Fisher are fantastic arboreal animals with joints that swivel 180 degrees allowing for swift movement up and down tree trunks while facing in the direction of travel.
Fisher are one of only two natural predators of porcupine (the other being mountain lion). Their startegy is to scare or 'push' their quarry to the end of a branch too small to support the porcupine's weight causing it to fall. If the porcupine is already on the ground or still concious after the fall, the fisher will circle the animal attacking its face causing it to collapse or go unconsious.
Fisher have 5 toes on both the front and hind feet, although the 5th toe does not always register or show up in the print. In this photo the left print shows all 5 toes pretty clearly.
Both front and hind feet have a metacarpal pad (palm pad) which leaves a distinct C-shaped impression that curves away from the toes (seen above). The fisher's front foot posesses a small heel pad which sometimes registers (not visible here). As fisher are sexually dimorphic, males (7-13 lbs) are larger than females (3-7lbs) and a typical male hind track can be up to 3 iches long while the female hind track may only reach 2.5 inches.
In the above photo, there are red squirrel tracks present at the bottom of the frame, below the fisher tracks. Both animal's tracks patterns are moving right to left in the frame.
The above photo demonstartes a typical 3-4 gait pattern exhibited by fisher. Simply, a grouping of 4 tracks in pattern, followed by 3 in pattern and so on (from bottom of photo to top).
Again a 3-4 gait pattern with toe drags registered between patterns.
It is a real pleasure to see fisher populations increasing as this species experienced a considerable decline in the 1800's/early 1900's due to trapping/overharvesting and habitat loss. Today fisher are slowly extending their range south into the northern reaches of the US.