• Conservation
  • Education
  • Policy
  • Lands
  • Centers and Events
  • About Us
Close this search box.

Winter Mammal Excitement at the Silk Farm Wildlife Sanctuary

Winter Mammal Excitement at the Silk Farm Wildlife Sanctuary

By Phil Brown
Tracking Porcupines:
A couple of months ago, during a cold spell in late December, I ventured off trail at the Silk Farm Wildlife Sanctuary in Concord in search of an interesting sparrow call note that proved to be that of a Fox Sparrow, an unseasonal winter visitor in our woodlands. It was associating with the more common Dark-eyed Juncos and feeding within an area of hemlock near Turkey Pond. Finding the sparrow led me to another delightful, but not really unexpected, discovery – that of a pair of young porcupines. Powdery snow had given away their telltale ‘snowmobile trail’ – their low heavy bodies plow right through fluffy powder and obscure any sign of footprints in such conditions. But last week, two months after my initial discovery, the snow conditions were considerably different. It was this kind of snow, sitting for several days without replenishment, that picks up all kinds of tracks. This was one of those days where entire stories of the forest came alive before my eyes!

Porcupine high in a Hemlock tree at Silk Farm Sanctuary, by Phil Brown.

It all started in the usual manner as my hikes do, making my way toward Turkey Pond on one of the several trails from my office at the McLane Center. The hemlock forest once again called me in, and I decided to make a periodic check on the sibling ‘porcupets’. A previous trip resulted in the sighting of just a single individual, and I had wondered if a Fisher had captured the other inexperienced sibling as Fishers are well-known predators of porcupines where their ranges overlap, occupying a niche market for a little-known delicacy of the forest. However, I was overjoyed to find both bundles of spines up in their usual places – a dead hemlock containing one, and the second just a couple of trees away, this one favoring live branches which provide more shelter and also its favored winter food source. Needles and bark, primarily, makes up the winter diet of a porcupine, and they are rarely found far from hemlocks during this season of scarcity. Certain hemlock trees have hosted porcupines for generations and exhibit a growth form that evokes images of a bonsai tree. When a porcupine finds a safe place with adequate food, it need not move very far, an attribute that makes it quite easy to spot, particularly in an area devoid of large glacial boulders that would otherwise provide a hiding place more out of sight. The best way to locate a porcupine is to look for an abundance of hemlock branch tips in the snow (or on the forest floor at other times of year) and simply look up!
But the day had other surprises in store. Another set of porcupine tracks led me to the edge of the hemlock stand and clearly revealed a fully-grown adult porcupine munching away on hemlock bark. They will feed by day (they sleep a lot, too) but are most active and on the move at night, when they must share the forest with potential predators like the Fisher. I followed a final set of tracks complete with pigeon-toed footprints and even toe registers in the snow (generally difficult to see in tracks of this species, but the right combination of crust and soft snow on a warm February day made it possible) to the base of a tipped-up white pine, exposing a cavity in the pulled up earth surrounding its roots. Here was the scene of a scuffle. Tracks, quills, and porcupine poop (the size and shape of shelled peanuts) littered the surrounding of the hole, and the whole place smelled like a petting zoo. Porcupines poop where they sleep – and seemingly, anywhere they travel. Tracks of a Coyote appeared at the entrance hole, and here is where several quills and soft, finer hairs, littered the ground. I suspect that the Coyote had nosed into the hole and gotten a whack full of bristles from the porcupine.
Tracking Fisher:
Further along on my hike, near the Old Orchard, I encountered another set of tracks – these in pairs and exhibiting a bounding pattern, the animal not sinking very far despite the soft snow – that of a Fisher. Somewhat surprisingly, the Fisher avoided the hemlock stand and the porcupines contained within. It must have seen something else on the menu, I thought, so I decided to follow the trail. Following a Fisher trail is plain fun! They lead the tracker on a tour of the largest pines and deadest snags of the forest, and their antics can be seen in how they navigate this landscape, going under or over or on deadfalls, and making lots of sudden turns. Fishers are known for tearing apart rotten stumps and dead snags in search of a favorite food source, the Flying Squirrel. So a tour of the forest quickly ensued as I tried to move like this fleet creature.
Squirrel fur and Fisher tracks, by Phil Brown.

My tour included the requisite dead snag and enormous white pine, another pine with a huge ‘midden’ of devoured pine cones (the telltale work of a Red Squirrel), a fallen tree that provided a nice runway for a short spell, and finally, the treasure I was hoping for – a kill! I could sense the excitement as I approached the site as an absolute mess of tracks surrounded a dark object. An apparently short chase by the Fisher indicated that a Gray Squirrel was its victim, only a frayed tail and two hind legs of it remaining on the scene. The Fisher worked hard to find its meal, but even its quarry was not the end of the story! Following more tracks, I noticed that both a Coyote and a Bobcat visited the gory scene a short time thereafter, and all converged at a large white pine. Here, I believe the Fisher escaped with its prey and probably remained as I scanned hopefully with binoculars for a dark, furry ball of sleeping Fisher…but it was not to be. The well-hidden Fisher was safe from its competitors and from its tracker.
Just another day out for a walk on the Silk Farm Sanctuary…many treasures await you, too!