Porcupine

Having got distracted by other things, I almost forgot about this. This is again from the east side of the cascades in Washington during a tracking intensive class.

Pretty early on we found these rather large porcupine tracks with the coyote tracks going along side. The coyote tracks look older (to me anyway), but are actually fresher - we found places in the trail where the coyote tracks wiped out the porcupine tracks.

A couple of characteristics I like in porcupine tracks are visible in the picture above if you click the image to enlarge it. First you can see the pebbly surface of their foot pad and second notice how the claws register in front and to the inside of the pads. If you aren't familiar with how claws show up in long-clawed animals, it might not be immediately obvious which marks are the claws. Looking at the picture though, there is a line a little in front of each of the tracks that angles backwards a little bit. Claws showing up like that and the inward angled feet seem to be pretty standard for other animals with long claws as well (e.g. badgers).

As fresh as these tracks looked, we hoped to find the animal. And there were many other porcupine tracks throughout the area we were looking. We expected them to be up in a tree during the day, and in that area they seem to really like russian olive trees, so we kept our eyes out. In can be a little difficult telling a porcupine apart from a birds nest or just a bunch of sticks/branches at a distance. Around lunch time Brian spotted this porcupine up in a tree out across a marshy area, so we all headed over to take pictures and look at it.

It had been in the tree for a little while as evidenced by some freshly chewed branches around the tree. As we made our way toward it, it climbed down the tree as if to head out away from us. As we got close, it thought better of it though and climbed back up the tree and watched us warily until we left.

Large Mystery

The trouble with planning to spread out several posts is that sometimes exciting things happen in the meantime and derail the schedule. We'll see if I get back to posting about my trip later.

For now I will tell you about some exciting things I saw while doing a transect for the Cascade Wildlife Monitoring Project up on the Snoqualmie Pass. I'm pretty sure we found marten tracks, but they weren't particularly clear tracks and with my lack of familiarity with them I'm not 100% confident of declaring them such without further consultation with someone more knowledgeable. There were also a couple of interesting small rodent mysteries that I may post about another time. But what I'm going to post about now has only become more mysterious for me as I continue to investigate it.

I found this set of tracks - apparently coming from a wooded area, going through a clearing and disappearing as it got to a stream bank. Tracks that large are generally of interest on the transect (and for me personally), so I was excited to check it out with the team. But not having all day to look at the tracks (having already spent a lot of time looking at what we believe to be marten tracks and still having another transect to complete) we took some pictures and measurements, discussed our thoughts and moved on.

There is a pretty clear pairing of tracks except in a few anomalous sets. I didn't think about it too much at the time, but because of the pairing had figured the animal was moving in an overstep trot. When I returned the next day I was a little shocked to realize that was probably not the case - that the anomalous sets suggest that all the other tracks were directly registering. That leaves me questioning which gait the animal was in let alone figuring out what animal it was.

If you have any thoughts or questions please post a comment. I would really like to figure this out as well as possible.

There wasn't much detail in individual tracks, but what there was looked mostly like this:


(the dark rectangle at the right is a ruler that is a bit over 15cm long)

When I measured the individual compressions I measured the whole way across since there was not enough detail to determine a true track. Also consider the likelihood that there were actually two feet landing in each compression. The individual tracks I measured were in part of the trail where the animal was moving somewhat slower then the speeds it later reached.

In the section of the trail where the first picture below was taken, lengths were from 11.8 - 13 cm, width from 12.5 to 14cm and the trail width was 18 - 24cm. The trail narrowed even more where the stride increased (as in the second and third gait pictures).

Most of the trail looked like the first two pictures below with what looked like a side trot or 2x2 direct register gait. However if you look at the third picture (or towards the background of the first two) you can see that sometimes there is an "extra" foot that would seem to rule out a side trot. The tape measure in the pictures is out to 6 feet. I will give some measurements of the tracks and gaits below the pictures.

Looking back the trail

Up the trail

Up the trail

Strides (assuming a 2x2 lope) were 84, 94, and 71cm in the slower section and when it sped up were 109, 112, 127, 109, 102, 105cm. The 112,127,109cm section was where there was an additional foot registering.

Group lengths were 46 and 54cm in the slower section and between 54 and 75cm in the faster section.

One further detail to be considered is that one of the extra feet, presumably a hind since it was the last in the grouping*, broke through and the hole was around 5cm across (I believe the compression in the hole was a bit larger than that though.)



So is it in a 2x2 lope, a direct register walk/trot with an odd pairing of tracks (a limp perhaps?), two animals travelling almost exactly in the same tracks, something else? Why does the track that breaks through not break the top out of the hole when the foot goes forward (perhaps the snow was to firm for the relatively lighter pressure of the exiting foot to break it)? And who was it?

*It is my understanding that oversteps are more likely to occur than understeps for most animals, particularly as the animal goes faster. Additionally there is some obscuring of the front track by the following track suggesting that the second track was made after the first one.

Of Holes and Rodents

I've been paying more attention to holes lately. The last couple of months I've spent some time considering differences between the western Washington mole species and their sign, perhaps that's what got me started. Regardless, while in California I spent a fair bit of time investigating holes. There are several different options down there that we don't have over here (though if you head to the east side of the cascades the options shoot up), so there was plenty to keep me occupied. Burrowing animals we found evidence of include ground squirrels, pocket gophers, woodrats, chipmunks, kangaroo rats and badgers. There was also a toad, but I'm not convinced it dug the burrow it was in (though it is my understanding the toads do dig some).

One burrow I dug out (best guess - a chipmunk burrow) had a plug of dirt an inch or two down, but once I got through that it opened into a small chamber with a few old juniper berries. The age of the berries made us think that the chamber had been abandoned. It also had a plugged tunnel leading off to the side.

I think plugged holes were one of the major themes for my hole exploration this trip. Some holes seemed relatively plug free, but many of them would seem to end except that the dirt would still be soft (while the dirt of the wall was harder) and easy to dig through until it opened up again.

When we were in the bay area there were places with numerous badger digs around. Many of them seemed to be only shallow digs, perhaps the size of my head overall, with a small throw of dirt in front of them. One we came too had a much larger dirt throw, but the hole was still the same size. This made me curious so I started digging through the dirt in the hole. It was quite soft and after I got a couple of inches down I found a side tunnel that was a hands width across - probably belonged to the critter the badger had dug out. But the badger hole kept going. I was quite curious what the deal was. Was the badger digging so far for its prey? Why weren't the other holes we found so deep? Why was it filled back in with dirt and where did the dirt come from?

As I got further in, it curved back a bit and began to open up. Eventually I had dug out as far as I could reach. We had fun sticking various body parts in the hole to see how far in we could get them.

Chain of Nature

My friend Roy introduced me to the idea of finding natural chains. This picture is an example of a three chain - a coyote ate a bunch of Russian olive fruits and then a mouse (I'm not actually certain it was a mouse, but it seems likely) came along and ate the seeds out of the resulting scat. One could perhaps count whatever animal had been eaten by the coyote (as evidenced by the hair in the scat), but I find it more aesthetically pleasing to limit myself to the direct chain. Though it would have been a fun addition to have found evidence in the scat that the coyote had eaten a mouse.

I've been away for the past couple of weeks on a trip to California and then the normal monthly tracking intensive. I've got a few things to share from those trips and so hopefully will get those posted during the next week or two.