Friday, January 1, 2010

Mustelid Madness

Lars was out on this beautiful day, at the northern end of Delaney Complex in Stow. The first set of tracks led me straight to the marshy kettle holes between the drumlins. Then one track led to another.

I followed this fisher down to the ice, where he was distracted by a second track. He comes in at the bottom right, picks up the scent, cuts off to the left, and immediately turns back to the track and follows it a second time. There were two sets of fisher tracks, one smaller than the other. According to Mass Audubon, mating season is in March/April.

Then farther down the kettle hole, a weasel (or mink?) crossed the fisher path (see blue box photo). I could see a nice bounding pattern, and a tail drag. The tail drag curls with a change in direction. I found tunnels and scat.

The last photo is at the edge of open water/open marsh. There were spots where the mink ducked in the water and out, with some short slides. Here the animal does a "to and fro". As he returns along the same path, you can see the tail drag curl in opposite directions.

The black ruler is 8 inches.


  1. Is otter a possibility for the larger of the 2 mustelids in the first photos? The toes are so prominent (otters have less fur on their feet), and the trail pattern looks like discrete groups of 4 tracks. Fishers often leave a trail in which the tracks within a group are more spread out, and the distance between groups is smaller, such that it is difficult to observe discrete groups. Not that it couldn't be fisher. Never say never.

    If they are both fisher, it is interesting to see a larger and smaller one on the same place. Males exclude other males, and females probably exclude other females, but a male will allow females to overlap part of his territory, and vice versa.

  2. Janet, I am not sure. I followed the two tracks for quite a while, and it seemed far upland for otter. Nor any tail drag. It went from the marshy bottom of one kettle hole to the next and then crossed woodsy areas, all of which were a couple hundred yards from open water or even a brook. I was off of Finn Rd (where I saw you and Dan once), off to the side of the northbound trail. How far do otter wander? I have other photos of the second track.

  3. I, too, think the tracks in the first shot look especially otter-like. Evidence of tail drag is rare, it seems, when finding otter tracks and slides. And otters have no trouble crossing through heavily wooded areas out of sight of water. Janet and I recently tracked otter climbing steep hillsides into dense woods. Their home ranges are larger than we generally expect, with some distance between ponds and other bodies of water that they frequent for feeding, etc.

  4. Well, if it kept up a pattern of tight groups of 4 tracks for all that distance you followed it, I would bet on otter, especially if it didn't slow down to explore snags and cavity trees.

    Also, I think I see webbing between those toes, but I can convince myself of almost anything if I stare at it long enough...

  5. This morning I was reminded of this "Mustelid Madness" while at Vaughn Hills.

    Soon after entering the Greed Rd trail head, I picked up a trail of beautiful 2 - 2.5 inch wide mustelid tracks, heading down hill. Lots of downhill loping and no sliding, so a fisher, of course, right? It was using its signature 6-6 bounding pattern...Huh? If there were 2 animals there, they both had feet of about the same size, so not a philandering fisher fling. Maybe a single fisher traveling again over its own tracks?

    The tracks took me down to the stream, where the animal finally did some sliding. And then the trail split into two separate trails, where I could see nice tight, discrete groups of 3's and 4's. Otters!

    One animal traveled back up the hill, occasionally sliding. I was fascinated to see how much downhill bounding and uphill sliding it did! (And there was no confusing the direction of travel - the tracks were super-clear.)

    A little later I picked up another trail of similar sized mustelid. I was sure I had a fisher this time, when I found 9 consecutive steps in 2-2 bounding....But then I back tracked it to a slide, and then a hole in the ice from where the animal had emerged, complete with a tarry black otter splat next to the hole.

    Then finally, further upland, I did find a fisher trail, with its messier, less discrete grouping, fooling around at the base of big trees, scent marking, and leaving a bit of blood as the only remains of a quick snack.

    I intentionally left my camera at home so I could limit my fun to 1 hour. Fortunately I bumped into John B., who was marveling at the same otter tracks, and snapping some pics. John, I hope you post them or send them to me to post.

    I got home 2 and a half hrs later. So much for the camera trick.