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Wednesday, May 15, 2013

Heard it through the grapevine...

The goal was to get some flying squirrel photos on the new (is it still new after three months?) Reconyx camera trap and I thought I knew just the place. We have an old massive gnarly black walnut in the backyard with some natural cavities and an impressive dead limb. I figured this might be where my flying squirrels live. So on April 27th at about 630pm I made a set using Squirrel Paste brand (made by On Target and sort of smells like nutty tobacco to me) as the scent lure.
Now, I need to confess right up front that I do not like heights. Even small heights. Any ladder-work is a challenge for me. I have been like this for as long as I can remember. I am not saying I don't do heights, I am saying I don't enjoy doing heights. So even this set at about 12 feet off the ground meant that I needed to negotiate the aluminum ladder each and every time I wanted to check my results.
And I checked them frequently. I checked nearly every day for two weeks. I had to. As the story unfolded, I was tempted to check TWICE a day. But I am getting ahead of myself...
Camera trap in black walnut tree
The Reconyx is ready!
It took 12 hours and 13 minutes for my first capture: a red squirrel. Not the target species but evidence that the Squirrel Paste was doing its job. Note this guy's nose buried in the lure.
Red squirrel on black walnut tree
There were a few more photos of red squirrels on the 28th, but it wasn't until that night that our target arrived! On my second trap-night I captured a visit by a flying squirrel (not sure which species). Please note its nose also buried in the Paste...
Flying squirrel photo with infrared flash

Turns out this was the only visit of a flying squirrel over the two week period. In retrospect, was this just a lucky capture? Imagine how high my hopes were when it only took two nights to get my first flying squirrel visit. Now imagine me trudging up that ladder every single day for two weeks with the increasingly sinking feeling that it was not going to return. On the one hand, I had technically accomplished my goal. But in reality, I was looking for multiple photos (and of much better quality) of multiple squirrels or displaying interesting behavior. In the end, there was no story in the night. The action was all taking place in the daytime and it took several days for me to uncover it.
My first visit to the Squirrel Paste by a gray squirrel came at 8:29am on April 29th. That is a latency to detection of about 38 hours. And again it was obvious that the Squirrel Paste was the draw.
Gray squirrel visiting Squirrel Paste (TM)
Although I went on to capture many images of gray squirrels at this set, the rest all appeared to be unrelated to the Squirrel Paste. In other words, I started catching photos of gray squirrels going about their business. Red, however, seemed to remain curious about the Squirrel Paste:
Red squirrel with nose buried in Squirrel Paste (TM)
But that isn't the story either. Just how many photos of squirrels with snouts full of "Paste" can one write about? (Apparently, four...) No, the story was a different attractant that just happened to also be in the old black walnut. Have a look at the following photo:
Red squirrel
While I was enjoying opening day of spring turkey season (always May 1 here in NY) with my Father, this red squirrel was licking sap off of this wild grape vine. The camera, centered on the Squirrel Paste, almost missed the action. Let's zoom in a bit:

I looked for more. And in very quick succession, I found these:

I wasn't entirely sure what this squirrel was doing. It could have been a marking behavior or it could have been feeding. If it was feeding, Gray didn't seem to want anything to do with it. Only a few hours later, he trampled past with one of last year's walnuts:
Gray squirrel carrying walnut
Let me sidebar here and explain a bit about what checking photos is like for me. As previously mentioned, I place the ladder against the tree, level it with a small branch and wobble my way to the top. I open the camera and swap SD cards and climb down with great relief. I enter the house, sit at the kitchen table and save all images to my laptop (while wiping the card clean). I then start to scroll through them. With the Reconyx, there can be hundreds of photos each day. I scan through them quickly to see if anything jumps out at me or if I capture anything particularly photogenic for class, Facebook or the blog. And since I had not captured any flying squirrels, I turned more and more of my attention to Red's antics over on the right side of the photos. I have the camera set to take a burst of three images when triggered and it was the following three-photo series that convinced me the red squirrels were feeding on the vine's sap. In the wee hours of the morning on May 2nd, bathed in the glow of the rising sun, this red squirrel showed he was using his tongue, not his teeth, to feed:
Photo 1: The approach
Photo 2: Licking the dripping sap
Photo 3: Not missing a single drop
This was amazing! Did the squirrel bite or "tap" the vine or was the sap running freely from a natural break? Were there other such feeding stations around the yard? Why were there no grays or flying squirrels taking advantage of the meal? Or no chipmunks for that matter? What did it taste like? And as importantly, what had I missed among the data collected from the last five days??? But first things first. It was back up the ladder for me to reposition the camera so it was aimed at the vine and not the Squirrel Paste. 
Once that task was completed, I set down to the more enjoyable job of sifting through the photos collected over the previous five trap-days to see what I may have missed. I encourage my students to think of camera trap photos as data. On this day, they felt more like clues to a mystery. I had to go all the way back to April 30th to find my first piece of the puzzle. Check out this image time stamped 1:16:56 pm
Gray squirrel
I probably only glanced at this photo for a fraction of a second the first time I went through this file. I didn't think it was a particularly compelling image of a gray squirrel then and nothing has changed in that regard. But have a look to the right of the squirrel -- the exact place where Red was so fastidiously tonging in the photos above. Do you see the droplet? Here, let's zoom in...
Grape vine sap
This is the first photo I captured that shows any visible sap from the grape vine. And the very next image actually shows it falling!
WOW! I think I was grinning from ear to ear here at the kitchen table. I mean, who would have ever noticed that drop of sap in the first place? Well, Red did. I took a photo when I re-angled the camera:

Wild grape vine dripping sap
Now I had the camera repositioned to better document the story, and just in the nick of time. Whereas on May 2nd there were only a few scattered visits to the vine throughout the day, on May 3rd it was almost a non-stop lickfest for the red squirrel(s). It takes some agility to reach the sap and I believe Red tried every trick in the book to get at it. Here are some of my favorites:

And the very best:

The visits were frequent and they often lasted several minutes. I made a stop-motion animation from the photo bursts:

But just as quickly as the visits increased, they began to ebb. 
May 4th: Few red squirrel visits in early morning. Last one at 8:40 am
May 5th: Slight flurry of red squirrel activity at vine at 6:25 am
May 6th: Only three visits. Last one at 10:30 am. No red squirrel photos the rest of the day.

I investigated myself the evening of May 6th.
Inspecting the vine
Vine covered with a white scale. I assume it is whatever was dissolved in the sap

I cannot detect any taste to the white powder
This IS my happy face...

The story was really winding down now:

May 6th: one last capture of red squirrel for the day, but no evidence it was visiting the vine

May 7th: One visit to the vine all day (at 9:50 am), but perhaps just a sniff sufficed:

May 7th 12:38 pm: On to other food sources.

 May 8 and 9: No visits to the vine. Convinced the story is over, I create new set in our "half-hedgerow" targeting raccoons. 

I never did find any other dripping vines in the yard (and we have PLENTY of grape vines), nor did I find any evidence that the red squirrel or anyone else for that matter had damaged the vine in order to make it leak. I did a little research on the vine sap and as expected, there is much written about it from a gardener or viticultural perspective. I saw several articles that referred to grape vines bleeding. I guess that is as good a term as any.

Thank you for hanging in until the end of this long post. I enjoyed telling the story almost as much as I enjoyed uncovering it. When I ask my camera trapping students to look at their photos and "tell me a story", this is what I mean. Of course, I can't tell a story like this at every set, but then again, maybe I am just not looking close enough...


  1. Oh, John. This is a great entry....your pictures, especially the 3rd one makes me laugh just as much as I "awwww'd" over seeing a squirrel tongue!

  2. What an incredible bit of behavior to catch on a cam trap! Well-done, JVN! I had a feeling that was your "happy face"....I see a similar expression these days when I look into the mirror, and I don't feel grumpy at all! :)


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