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Wednesday, February 25, 2015

Winter tracking: Red Fox

This winter has been marked by a large amount of snow and long periods of below freezing temperatures. Although the temperature was only about 24F it was sunny and I strapped on the cross
Red fox
(Seneca Falls, NY 2/15)
country skis to retrieve one of my camera traps. Turns out there has been a lot of fox activity at that site, both red and gray. At right, a red fox noses under the snow for food.











Next, a gray fox appears after a fresh snow:
Gray fox
(Seneca Falls, NY 2/15)
Red fox leaving a trail in the snow
(Seneca Falls, NY 2/15)


I have been looking at animal tracks in the snow for years. Tracks and trails in the snow are often easy to identify. Up until recently, I have been focusing exclusively on the track itself. This winter, I have paid attention to the changes to the snow below the track. The weight of the animal compresses the snow, packs it down and makes it harder. If you find a trail that has fresh snow on top of it, you could try to gently brush away the new snow and uncover the harder lumps left behind. you could confirm track size, gait and perhaps even direction of travel.
What I found today was a bit different. Instead of fresh snow covering an old trail, I discovered an
Two red fox trails
(Seneca Falls, NY 2/15)
old trail that had been scoured by strong winds. The hard compressed snow at the bottom of each track remained while all the other snow was whisked away. In the photo at right, the new trail is towards the bottom of the screen and the older trail is above that. Both foxes are travelling to the left. You can see the shadow of my head in the photo for some scale.






Old fox tracks that have been scoured by wind
(Seneca Falls, NY 2/15)
Here is the same scene but a bit closer. I know that photos of tracks can sometimes produce an optical illusion and it is difficult to see what is depressed and what is raised. In this photo as in the one above, the upper most trail is raised and the lower trail is the fresh trail with impressions in the snow. If you look closely at the upper tracks, you can see that they are almost an inch above the rest of the snow.





Here is another view. What is amazing here is that for three steps, this fox matched the old trail perfectly. There is a good chance that this is actually the very same fox taking the very same trail maybe a week apart. I have added some shadow here to provide some depth to the photo. Can you tell the direction of travel? I can.







Compare a fresh and old red fox track in the snow.
(Seneca Falls, NY 2/15)
There are two pieces of evidence that I can see in the photo that tell me the old trail is heading towards the top of the image. First, if you look closely you can see the faint impressions of the toe pads as well as the palm pad. They are faint, but they are there. Secondly, notice that there is a slight uptick to the hard pack at one end. That is the back of the track. It is literally the spot where the leg itself bore some of the weight of the animal as it stepped in the snow




Red fox track
(Seneca Falls, NY 2/15)
I scooped the track up and held it in my hand. I smiled thinking that I was probably the only person in the world that was holding a fox track at that very moment. I turned it in the bright sunlight to catch the shadows along the surface. I scraped off all the excess snow until I was left with the hardened lump. I was pleased with myself. It had been a good walk. I felt the cold track in my bare hand and thought of the animal that had made it. It was time to head home. On an impulse, I took a big bite out of the fox track and dropped the rest. A perfect ending to my lesson in the snow.


Tuesday, February 10, 2015

Winter shrew

We have an old farmhouse that features an unfinished basement. Consequently, we have mice more or less all the time. But over the weekend my wife reported a dark ball of fur darting past the washing machine and she concluded: It was a shrew. So I set a Sherman trap baited with peanut butter and within hours, I captured a short-tailed shrew. I placed him in a cardboard box and took a bit of video with my Go Pro. Got a minute? Watch the video here.

I wanted to get some photos of the shrew in snow but I didn't want to just release him outdoors. We have had a very cold winter so far with lots of snow. Letting him go outside might jeopardize his survival. So I came up with a different plan. I filled a large Tupperware container with snow and placed the shrew in it. I hoped that I could snap off a few photos before the shrew bolted for the dark corners of the basement. Much to my surprise, the shrew tunneled through the snow and climbed on the edge but refused to leave. I got my photos and then gently returned him to his adopted home.

One defining characteristic of our shrews is the dark enamel on the teeth. There are white-toothed shrews elsewhere in the world, but our shrews all have dark teeth.
Short-tailed Shrew
(2/15, Seneca Falls, NY)

The short-tailed shrew is very common and may be the most common mammal in New York State. They have small eyes and no visible external ears. They are NOT rodents and therefore not closely related to mice. In fact, the short-tailed shrew can actually prey on mice with their venomous saliva.
Short-tailed Shrew
(2/15, Seneca Falls, NY)
Aaaahh.... :) Check out the tiny black eye visible in the photo below. The real story is those whiskers though. This is an animal that uses scent and touch more than vision.
Short-tailed Shrew
(2/15, Seneca Falls, NY)
Shrew tunnels are smaller in diameter than mouse tunnels. Shrews are active all year and require an enormous amount of calories each day. I have read that the short-tailed shrew specifically takes in 75% of its own weight each day. In that is a lot to find in the subnivean world.  I hope my shrew ingests lots of spiders and maybe even some mice in that basement of ours!
Short-tailed Shrew tunneling in the snow
(2/15, Seneca Falls, NY)
Did you remember that this was all staged in a little Tupperware full of snow? Here is the shrew getting up on the lip. But after a moment, it was back into the snow!

One bonus photo: Shrew scat. Whether you call it shrew poop, shrew scat or shrew droppings, it is all the same thing. I am not sure how typical this scat is, but it looks very different than the pellets that are produced by mice.
Shrew scat
(2/15, Seneca Falls, NY)
Thanks for reading. Check out my other shrew posts to see a shrew nest and some baby short-tailed shrews.