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Black Bear Cambium Feeding in Ontario?

Many current and former Earth Tracks Tracking Apprenticeship apprentices were participating at a recent Track and Sign certification in Parry Sound, Ontario evaluated by Sage Raymond. On the second day of the evaluation, there was sign on at the base of a Eastern White Cedar (Thuja occidentalis) where a good tall triangular section of bark was missing and the remaining bark had begun lobing over towards the exposed wood. The cambium layer, sometimes called sapwood, where the tree sends nourishing sugars up from the roots out to the shoots and leaves of the tree, was missing. This wound seemed to have occurred a while ago, and, as noted above, the tree was healing as the remaining bark was enclosing the wound.

Above and also to the sides of the lobing over bark, there were some longer stringier strips of bark which were dangling from the peak of the wound. There also appeared to be some sort of epicormic growth at the peak, where newer, smaller branches were growing in response to a wounding in the tree. Sage considered this a bonus question, a really hard question, in the evaluation and took multiple answers, none of which I proposed. One of the purported causes of the sign was Black Bear (Ursus americanus) feeding on cambium, a behaviour I have heard about and seen photos of before, but never witnessed here in Ontario.

Sage Raymond is an accomplished tracker, the only Canadian evaluator with Tracker Certification North America (TCNA), a Bear guide out West, where she leads groups out through wildlands to encounter Bears safely. I believe she knows what she is talking about and has a lot more experience than I do. But, and I bet you knew that was coming, I felt and still feel a little iffy on the possible Black Bear cambium feeding as a possible behaviour which created this sign. So, I decided on that day of the evaluation that I will do my best to learn more about Black Bear cambium feeding sign and see if I can find more examples here in Ontario.

Firstly, I want to acknowledge a few things. I got the question wrong, and sometimes when we get things wrong, our egos can get a little bruised or wilty. I want to remind myself of that and hold on to that knowledge while trying to research. Am I just frustrated I was wrong or am I looking to deepen my understanding of another animals behaviour? Personally, I am so grateful to learn new things, and am pretty stoked that trackers may have noticed a possible behaviour of Black Bears in our region that naturalists of all sorts have failed to spot up until now that it’s pretty exciting to be wrong here. Or instead of “being wrong”, to be learning something new. It’s not about boosting my ego, more so getting to know the eco.


Fast forward a couple of weeks and the Earth Tracks Tracking Apprenticeship is out again, this time at Noisy River Provincial Park, along the Bruce Trail when following an older snowed in canine trail two colleagues came across more sign just like the possible Black Bear cambium feeding we saw up in Parry Sound!

Similar sign on Buckthorn adjacent to Cedars.

At one spot there were at least five Eastern White Cedars which were all damaged in apparently similar ways. All of the wounds arose from the base of the Cedars where they were widest, and then rose up to a narrowed point at heights between 75 cm (nearly 30 in) , 80 cm (roughly 32 in) and 120 cm(almost 4 ft). Some of the wounds had long strips dangling from the sides, similar to what was seen in Parry Sound, and all appeared older than two years. Along the opened wound a couple had vertically oriented pale spots which some of the folks at the outing felt were indented into the wood. They were thinking that these could be the marks of the incisors from the possible bear which had made these signs. Adjacent to the Cedars, I also found a Common Buckthorn (Rhamnus cathartica) with similar exposed wood, free from cambium, looking about the same age, though without the dangling strips or the pale possible incisor marks.

Now, before moving on, I want to look into how this sign is described in the literature and then compare with what we saw.

In Mammal Tracks and Sign 2nded (Elbroch and McFarland, 2019) they write:

Black bears are also notorious eaters of tree cambium in the west and northwest of North America, where this behavior has become an intensive subject of both research and intervention to mitigate losses to tree farms. This sign varies depending upon tree species and the age of the sign. Fresh sign is often light in color, changing to red, purple, and orange as it ages, again depending upon the tree species. Bear sign on cambium may look like large patches of missing bark were chewed off on a western hemlock… or large strips of bark were peeled off when the tree is a western redcedar… Cambium feeding occurs when sap is flowing and the bark separates more easily from the sapwood; patches or strips are often removed all the way to the base of the tree, readily differentiating it from sign made by antlers. Teeth marks often become more apparent as the sign ages…, and extensive foraging often results in the death of the tree.

White-tailed Deer feeding on the cambium of Speckled Alder.

First thing I note in the description is that this behaviour happens out West. I believe it has only been recorded in the East once. This doesn’t mean that it doesn’t happen here though, just that it is more apparent, more researched and more widely understood out West. Secondly, about the teeth marks. I am unsure what we were seeing were teeth marks when compared with what I have seen online. The gouges I have seen in books and images online are longer, narrower and similar in appearance to ungulate incisor marks when they are seen feeding on bark and cambium. I also want to mention while White-tailed Deer cambium feeding is also pretty rare in Southern Ontario, yet this year I found some sign of this behaviour on Speckled Alder (Alnus incana) down close to Hamilton, Ontario. So there are no hard and fast rules about animal behaviour solely occurring in one region and not in another. I will also add that the characteristics of a sign will change and alter over time, and while I can see noticeable clear individual incisor marks when made fresh, we may loose some detail as the sign ages.

In the field guide Wildlife of the Pacific Northwest (Moskowitz, 2010), it says:

In many parts of our region, bears feed on the cambium of trees, including Douglas fir (sic), western Hemlock (Tsuga heterophylla), Western red Cedar (Thuja plicata), true firs (Abies spp.), and Black Cottonwood. They peel down the outer bark with their claws and scrape off the cambium with their lower incisors. In some forest, these signs are prolific yet often overlooked. Though this type of sign is visible year-round, this behaviour is most common in the spring.

This helps bring more context to the possible Black Bear cambium feeding, both in Parry Sound, and at the Noisy River, as they were both found on another Thuja species. Maybe Black Bears both near and far have a taste for Cedars?

The book with the most to say on Black Bears feeding on cambium seems to be Preston Taylor’s self published Tracking The American Black Bear (2021) which dedicates four long paragraphs to the phenomena, one of which details how the Black Bears actually access the cambium. Preston Taylor writes :

Bears claw at the bark to start the strip, grab a piece in their teeth, and pull the strip off the tree, sometimes more than 20 feet long… once the inner bark is exposed, they scrape it off the tree to eat. The feeding sign of bears on cambium presents itself in different ways based on the species and character of a tree. Easily stripped, young, smooth, growing trees, display, long, vertical grooves on the tree after the bear has fed. Trees with burls and sprouts, like Port-Orford cedar are too knobby for a bear to feed on the cambium in long grooves, so they take short – horizontal scrapes off the inner bark.
The pattern left on the tree is more a patchwork resembling porcupine feeding. The grooves in the tree’s wood, whether long or short, are from the bear’s incisor teeth.

I want to also keep this in mind for the future; Black Bear cambium feeding may appear differently based on the type of tree they are feeding on.

A final point he makes which I thought was interesting to note was that he believes that this cambium feeding behaviour is a learned behaviour. This could be a reason why we do not see it, or very rarely do, in the East as this feeding behaviour may not be as important a part of the Black Bear culture here, as it may be in the Western part of Turtle Island/North America.

In my research I also found a short video on youtube which shows a Black Bear demonstrating the cambium feeding behaviour:

Many Northeast tracking guides do not mention this cambium feeding sign from Black Bears as it may be uncommon in the Northeast. One publication by the US Forest Service (Nolte, D.L., K. Wagner, and A. Trent. 2003, linked below) named that this behavior and associated sign as occurring nationally, implying that it does occur in the Northeast, but perhaps it is just not as economically problematic, therefore, not researched or discussed?

I did find a single article, by accomplished Black Bear tracker Sue Morse, writing of her experience in Vermont in 1984. The article starts with this:

..I discovered some curious bear feeding sign on a mid-elevation ridgeline in northern Vermont. A pole-sized bigtooth aspen had been peeled to its roots like a banana. Strips of bark lay in tatters on the ground, and the exposed wood was scored with vertical groupings of parallel scrape marks caused by a black bear’s incisor teeth. Since then, I have observed this feeding behavior on balsam fir, young sugar maple, red pine, and red spruce.

Sue’s experience is pretty helpful in building the evidence.

Black Bear cambium feeding on Walnut in MA, USA. Photo by Bob Etzweiler. Thanks, Bob!

While there were some papers I found online which featured some research done in the Northeast, no peer-reviewed papers mentioned researchers observing Black Bear cambium feeding in the Northeast. But the researchers don’t always know what the trackers know (and vice versa). I personally reached out via email to some well-respected, and accomplished trackers in the Great Lakes Region, no one had observed Black Bear cambium feeding sign. But just East of the Great Lakes in the New England area, same region as Sue Morse, Bob Etzweiler did reply saying he has observed Black Bear cambium feeding sign “a small handful of times” in the Northeast, but he included that this sign is thought to be “not very common” in the area. This then implies that it does happen, just not too often. Which is also helpful and it seems like the anecdotal evidence is starting to build up. Bob mentioned that this is consensus with his tracking friends and colleagues. He also sent a photo of cambium feeding on a Walnut (Juglans sp., likely J. nigra) in Massachusetts, which was super cool to check out (shown on left).

Recently at work I took a small tour around our Eastern White Cedar forest to see if I could notice any sign that may look like what we saw up in Parry Sound or what we found at the Noisy River. I did come across a few Cedars which looked similar, but after closer inspection, I could easily see signs that would tell them apart; bare patches not reaching all of the way to the ground, or bark stripping not going higher than a metre. I did find a couple of trees which could fit the specifics of what we found, including what folks pointed out as aged and faded incisor marks. I took a few photos which I have included below.

 

I believe that these are just trees which have survived some sort of damage and are either in the process of healing over, or have died, and the bark looks similar to that of Black Bear feeding sign. I do not believe they are sign of Black Bear feeding on cambium even though they look similar to what we found in Parry Sound and the Noisy River as we do not have any consistent population of Black Bears in Guelph and have not had any known Black Bears visitors in this part of Guelph for many decades.


My hope is to continue to look for Black Bear cambium feeding sign. This sign is similar to many other tracks and sign I have encountered in that I may have never seen it before, but once I do I start to see more commonly; I only begin to see the characteristics and slowly pick out the patterns. My hope is that this process of research and reflection help to tease out some details which I might miss, while also leveraging any doubt and uncertainty towards being a better tracker. While I may sometimes wonder at whether a sign is what others point out or not, I would rather do the research and be on the look out, rather than to ignorantly dig my heels in on a stance that I honestly don’t know that much about.

I am grateful to the bears for leaving sign to cofound, confuse and encourage me to keep learning. To my tracking colleagues at Earth Tracks, to TCNA evaluators like Sage Raymond who show me things I have never seen before, and to all those who help me along this path.

To learn more :

Timber Damage by Black Bears: Approaches to Control the Problem. Nolte, D.L., K. Wagner, and A. Trent. 2003. US Dept. of Agriculture, Forest Service. (pdf)
Mammal Tracks and Sign, 2nd ed. by Mark Elbroch and Casey McFarland. Stackpole Books, 2019.
Wildlife of the Pacific Northwest by David Moskowitz. Timber Press, 2010.
Tracking Tips: The Ap-peel of Cambium by Sue Morse
Peterson Reference Guide to the Behavior of North American Mammals by Mark Elbroch and Kurt Rinehart. Houghton Mifflin Harcourt, 2011.
Natural History of Canadian Mammals by Donna Naughton. Canadian Museum of Nature and University of Toronto Press, 2012.

Highlights of Tracking in the Boyne Valley

I have been thinking a lot this Winter about how amazing it is that all of the various species we track can survive such apparent hardships of freezing temperatures, labourious snow depths, and drastically reduced vegetal forage. It’s like turning off the heat in your house, wading through 60 – 90 odd cm (2 – 3 ft) carpet pile, while constantly engaging all your senses to find the perpetually vigilant and furtive refrigerator. Tough times indeed.

So while out the Earth Tracks Wildlife Tracking Apprenticeship program in the Boyne Valley, I had an eye to how some of the animals were making their ways across the landscape, what they may have been eating along the way, and see if I could learn a little bit more of the local ecology here in Southern Ontario .

Directly beside the Bruce Trailhead parking lot there was a stand of Staghorn Sumac (Rhus typhina) shrubs and located between 90 – 180 cm (3 – 6 ft) high along the trunks were sections of exposed wood where the bark had been chunked away and discarded on to the snow below. There were short, mostly vertical grooves left in the cambium layer of the trunks, grooves which were about a third to half a millimeter wide (1/64 in). They appeared to be incisor marks scraping away the cambium layer for food.
From a distance, I could mistake this sign for that of a Porcupine (Erethizon dorsatum), but all of the branches close to the exposed areas were much too thin and fragile to support the weight of a Porcupine and the marks would have been too small for a Porcupine’s incisors. Instead we started to consider other possbilities of smaller animals than Porcupine, even though the signs was high up and the snow pack was deep, it was not as high as the sign. Could it have been from deeper snow pack from a previous year? N0, as this was certainly fresh sign from this Winter. If it were from last year, there would likely be some discolouration at the edges of the feeding area, and some speckled mildew growing on the exposed wood.
Which local species can climb, and feeds on cambium, has tiny incisors? Our minds went to Vole. There are two voles in the area, Meadow Vole (Microtus pennsylvanicus) and the Southern Red-backed Vole (Clethrionomys gapperi), but the habitat gave us some clues. While Meadow Voles prefer meadows, prairies, fields and woodland edges, the area we were in was mostly forested. Sure, we were at the edge of said forests, but thinking of all the clues, we began to lean towards the Red-backed Vole. Who among the two vole species named has smaller incisors? It’s the Red-backed, coming in at an average of .62 mm for the lower incisors and up to .80 mm for the uppers (teeth are measured in millimeters), while the Meadow Voles range between .98 mm for the lowers and 1.25 mm for the uppers. Another point for the Red-back. Do Red-backs climb and feed on cambium? They do climb trees, but feeding on cambium is uncertain. Meadow Voles certainly feed on cambium and I have found dozens of examples of this behaviour, and I would assume the same for the Red-backs. Really though, it would be nice to have direct empirical evidence when observing familiar sign from a species I have not seen making that sign before, or at least read about someone else’s experience of the sign. Some lingering questions remain. Can we be certain it was a Red-backed Vole? Are there any differences in their sign that would help us distinguish them in the future? Do Meadow Voles climb high into trees to feed on cambium? Does either vole species in my area have a preference for Staghorn Sumac? Would the parking lot beside the sumac affect the qualities the voles are looking for? These may never be answered.

We moved across the road and through the Eastern White Cedar (Thuja occidentalis) forest and slipped down a steep hill into an open river meadow dotted with melted out tracks of White-tailed Deer (Odocoileus virginianus), Meadow Voles, and Coyotes (Canis latrans). As we walked along these trails we also came across a spot in the snow where there were two Brown-lipped Snail (Cepaea nemoralis) shells sitting at the base of some Goldenrod (Solidago sp.), Virgin’s Bower (Clematis virginiana) and Raspberry (Rubus sp.).

The shells were empty of their creators and because of this it reminded me of a paper I read from 1907 about Short-tailed Shrews (Blarina brevicauda) and their habits of piling up discarded snail shells in Winter. It was a unique paper and the writing a bit dated making the whole thing enjoyable to read (there is a link to the paper below). Anyways, when trying to discover the piler, the researcher found, through interesting means, that the likely species was the Short-tailed Shrew. One sign to look for when finding these piles of snails in Winter is small holes, burrows or tunnels nearby. While it wasn’t exactly clear, there do appear to be holes into the subnivean (under the snow) at the base of the forbs.

I wish now that we had checked some of the shells out better. I noticed one the shells had a smooth cellophane like covering over their aperture, the hole where the soft body of the snail emerges from the shell. This covering is called an epiphragm, and the snails create it with their slime to seal off the aperture to prevent dehydration while they hibernate in the Winter. While I noticed this on one of the shells, I do not remember if this was present on the other shell. I also not remember finding any sort of crunching into the shell around the apical whorl, which is the middle area the spiral of the shell. Crunching a hole in the apical whorl is a common way for Short-tailed Shrews to gain access into the shell so they can feed on the snail within. The shrew may also gain entry through the epiphragm, but if that wasn’t broken either, than perhaps the shrew had simply discarded the shell without consuming the snail?

And while I was a little cautious in this identification because there were only two snail shells, the writer of the 1907 paper found piles with as few as two or three up to a hundred shells discard in a midden pile! I believe my shell pile record would be about 20 or so shells at the base of a Manitoba Maple (Acer negundo) a few years ago. When hunting for snails the Short-tailed Shrew collects them, bites the snails and then caches them somewhere within their tunnel system, and often under logs. The snails cannot escape because Short-tailed Shrews are also one of the very few mammals with venomous saliva, a venom which can cause their small prey to have breathing trouble and circulation issues. It also leads paralysis and maybe even death. It’s pretty cool but also pretty spooky for the snails. I am also wondering if Short-tailed Shrews going after Cepaea snails in my area is unique? None of the papers I looked at mention Cepaea species in relation to Short-tailed Shrew diets In reflecting on this small, possible midden pile, I realize that I must look into the signs we find a little bit more when I find them in the field.

As we moved on, what we had thought earlier had been a Coyote trail proved to be true. The trails were set in shallower snow under the shade of a tunnel of Eastern White Cedars and followed a human trail a little ways up from the river. A short ways into the tunnel of cedars we came across a Coyote scat.

There appeared to be a lot of it as well. The diameters were well over 2 cm (¾ in) and they appeared to be full of chewed up Apples (Malus domestica).

Coyotes eat a lot of Apples. If there are Apples around, and Coyotes around, you’ll find Apples in the Coyote’s scat. When in proximity to human development and habitats, Apples are an easy to find food source that they don’t have to expend a lot of energy trying to run down through deep snow. But I wonder at how much energy is expended in trying to acquire to the Apples, and how much they get in return, especially when the scat appeared as if nothing had really broken down the Apples and little nutrition appeared to be pulled from them? I can’t find much information online about the energetic outputs of Coyotes digging in snow, nor the energetics they acquire from consuming Apples, but what I do know is that Coyote digestive tracts are short relative to humans and herbivores, and the Apples they consume must move through the digestive tracts quite quickly. They must probably consume a large quantity, with little energetic return (based on the observations of the content of this particular scat and many others I have seen). Why then do the Coyotes consume so much Apple if they don’t appear to get much from them? It might just be because it is there, it fills their belly and may even act in a similar way that grass eating does for some other canids – the chunky bits help to “scrub” their digestive tracts and the fibre keeps them regular? I can’t know for sure, but the quick carbs and bit of hydration from an Apple may also be helpful.. but how much do they really digest?
One paper I read from a study in Calgary, Alberta said that Crabapples (Malus spp.) made up about 33.88% of Coyote diets between August 2006 -September 2007. That’s a third of their diet! Since Apples persist through the Winter, it makes sense that this could be a common food source for them in Winter. Another cool thing that was noted in the paper (linked below) was that Coyotes seemed to consume less anthropogenic food items in the Winter than in any other time of year. This might be because humans spend less time outside in the Winter and that might mean less human trash strewn about for Coyotes to get a hold of. Interesting…

As we wandered on, we came across a fairly clear looking Fisher (Pekania pennanti) trail. It wasn’t so clear in the beginning but as we walked along and the search image of the track became more and more burned into our minds, the trail stood out like blood in the snow.

I filmed a small section of the trail and say in the recording that the tracks were 6 cm (2⅜ in) wide, and that I measured about 8.89 cm (3½ in) trail width on the 2×2 lope.

I believe it was only a moment after I stopped recording that we realized that there were actually two Fisher trails, with one trail showing larger tracks than the other trail, perhaps indicating a male and female? From memory, one of my colleagues who was there recalled the tracks of the two individuals as being 5.75 cm (2¼ in) and 7 cm (2¾ in). Perhaps in the video I was following the smaller of the two, which is kind of awesome, considering that 6 cm track width would be from the small one!

As I mentioned above, we were wondering if the two Fishers were a male and female moving together? In my research I have been looking at the amazing book “The Fisher : Life history, ecology, and behaviour” by Roger A. Powell (University of Minnesota Press, 1993), and in that book Powell cites two interesting papers attempting to see if we can tell the sex of a Fisher based on different measurements of the foot or foot pads. Here is the quote :

Trappers’ accounts and early scientific reports claimed that it was possible to determine a fisher’s sex by its track size. Coulter (1966) measured the hind-paws of 38 male fishers and 27 female fishers. The lengths ranged from 8.6 to 12.5 centimeters in females and from 10.0 to 13.5 centimeters in males. Johnson (1984) measured the pad dimensions of 10 male and 8 female fishers. Lengths of neither forepaw nor hindpaw foot pads differed significantly between the sexes, but widths did. The widths of forepaw pads averaged 4.8 centimeters (range 3.8-5.4) for males and 3.9 centimeters (3.8-4.1) for females; the widths of hindpaw pads averaged 4.7 centimeters (3.8-5.1) for males and 3.9 (3.5-4.5) for females. Even though the distributions of the total length of hind-paws and pad widths of fore- and hindpaws were different for the two sexes, the dimensions overlapped, except at the extremes. Thus, it is not possible to determine positively a fisher’s sex from its foot dimensions or track size unless the foot length is less than 10 centimeters or greater than 12.5 centimeters (this occurs in only about 15% of fishers) or unless the width across the pads is less than 3.8 centimeters or greater than 5.4 centimeters.

I wish I had understood these ranges before hand and could have considered them in the field and tried to measure for the differences. Another means of possibly sexing Fishers in the field is noting if they have climbed any trees while you are following their trails. Here is a quote from the species profile on Fishers from “Mammal Tracks and Sign, 2nd ed” by Elbroch and McFarland (Stackpole Books, 2019).

Competent climbers, and spend time hunting in the trees as well as on the ground. However, large males spend considerably less time in trees than do the much smaller and lighter females, so much so that climbing itself is a decent indicator of the sex of the animal that made the trail you are following (Powell 1993).

We followed the Fishers along a downed Cedar which acted like a shaky bridge across the Boyne River, and up a fairly steep incline until we came across a spot on the trail where the Fishers had intersected with an Eastern Cottontail (Sylvilagus floridanus), only all that remained of the Cottontail was some loose patches of fur, some snow diluted blood, and a piece of the premaxilla and some incisors.

I couldn’t tell if the Fishers had killed the Cottontail, or if they had consumed any, or interacted much at all with the Cottontail. The mortality site seemed older than the Fisher trail and there were no sign of Fisher tracks in the midst of the Cottontail remains. If I remember correctly, the Fishers skirted the site and moved on towards a large pile of fallen trunks and branches of more Eastern White Cedars. Sometimes this is called Course Wood Debris (CWD) and this is great for Fisher nesting, so I wonder if either of the Fishers will be back come birthing season come Spring?

We too headed towards the CWD and clamoured over it all and right in the center of the pile was a depressed area, still covered with snow where there was two more tufts of Cottontail fur as well as two scats, one wider and longer than the other. These looked like Fisher scat, though the larger one was larger than what I have found in the past.

When we broke up one of the scats we noticed that it had some bone fragments and coarse hairs, which may have been a little bit darker than most Cottontail hair I have seen though there may have been hair from multiple animals, but more than likely, the scat was probably filled with hair, bone and the debris of Cottontail remains. It seems that the Cottontail is a big part of the Fisher diet.


I want to jump ahead to the following day because there was an important discovery made while we were walking again along the Boyne River, heading East, along with the flow of the river.

I believe Alexis was ahead and had stopped as he had noticed something out of baseline amidst the woody debris in the snow. When I walked up I stopped and noticed it as well. Ahead of us, upside down in the snow was the skull of a White-tailed Deer. We stood silently for a few seconds taking in the scene and scanning the area. The others were catching up and as they did, I slipped off to check out a mandible which, too, was nearly covered in snow, with only the half chewed coronoid process sticking out from the blanket of white.

We decided that we should all take our time to explore this area and see if we could discover anymore remains of the deer as this looked like a spot where, likely, some Coyotes were feeding on the remains.
As everyone searched, a couple more pieces were found, including a leg, a piece of one of the scapula, and a loose thoracic vertebrae.

We decided to stop here in this spot for lunch so we could better take our time and examine the bones we found in hopes of learning a little bit more about the deer and the Coyotes who were feeding on the remains. First I believe we looked at the leg and tried to determine which leg of four it was. We determined the leg was a front leg based on the presence of the ulna and radius bones which are only found on the front legs of deer. Since we then understood that this was a front leg, we then looked at the proximal end of the metacarpal bone to examine which side was wider – the wider side being the medial side, toward the midline of the body. The wider end was on the right, implying that this was the left leg. For a detailed look into how we determined left vs right from a metacarpal bone, check out this post here.

Left front leg of a White-tailed Deer

What I was curious about when we looked at this was the shape and location of the break on the both the metacarpal bone as well as the humerus. I have seen long bones broken like this before and have heard on an online track and sign study call in the past that this is similar to how wolves break the long bones of their prey. Is this form and location of the break indicative of large canids? Can we use this as a tell-tale sign that canids have been feeding on the carcass? The fracture on the bones sort of spiral or curve around the shaft of the long bone. These are called helical or spiral fractures as they curve like a helix around the shaft. These fractures are a fairly common find when a few different carnivores consume an animal with long bones such as deer, Moose (Alces alces), or other Cervids. Many bears (Ursus spp.) and canines (Canis spp.) will leave sign like this on long bones.
Why may carnivores break these bones? The inside of the bones enclosed the bone marrow, which is full of fat, collagen, vitamins and minerals which are very helpful for any animal and gaining access would be a very worthwhile endeavour. This sign is something I will be looking for more of at mortality sites in the future.

We followed a few more interesting trails from this spot, including a pretty fresh Coyote trail, with very fresh scat, but I am feeling like this blog post has gone on beyond my own interest in writing it. Check out the books and links below if you want to learn more.

Big thanks to my tracking colleagues for this great and memorable weekend of adventure.

To learn more :
Animal Skulls by Mark Elbroch. Stackpole Books, 2006.
Vermont Mammal Atlas entry on Southern Red-backed Voles
Arboreal behaviour of the red-back vole, Clethrionomys gapperi. Animal Behaviour 16:418–424. Getz, L. L., and V. Ginsberg. 1968.
Habits of the Short-tailed Shrew, Blarina brevicauda (Say) by A. Franklin Shull. The American Naturalist, 1907.
Conspecific Killing and Cannibalism by a Free-Ranging Northern Short-Tailed Shrew (Blarina brevicauda) by Brent M. Graves & Suzanne M. Petschke. Northeastern Naturalist, 2026.
Spatial and Temporal Variation of Coyote (Canis latrans) Diet in Calgary, Alberta by Victoria M. Lukasik and Shelley M. Alexander. Cities and the Environment (CATE), 2012.
The Fisher : Life history, ecology, and behaviour by Roger A. Powell. University of Minnesota Press, 1993. (link to archive.org library copy)
Mammal Tracks and Sign, 2nd ed. by Mark Elbroch and Casey McFarland. Stackpole Books, 2019.
Metacarpal or metatarsal? blog post at toknowtheland.com

Signs of the White-tailed Deer Rut

I was out with the Earth Tracks wildlife tracking apprenticeship at Mono Cliffs Provincial Park the other day, tracking with the intention to trail some White-tailed Deer (Odocoileus virginianus). This is a challenge for me. Not the finding of tracks, but the following of trails in anything but mud and snow. Leaf litter, even in the wettest of leafy debris is a struggle for me so it was a good day to watch and observe others who are better at trailing than I am, while also working on my own skills when the substrate got easier to read.

We started walking East in an alley of Spruces, mostly Norway Spruce (Picea abies) and everyone started to veer South towards an open field of Goldenrods (Solidago spp.) and Asters (mostly Symphyotrichum spp.). I ended up staying in the Spruce alley as was finding some interesting Coyote (Canis latrans) scat composed mostly of Apples (Malus domestica). This is something I have seen a lot of this time of year and while I am still impressed, I didn’t spend a long time with the Apple scat. Instead, my attention was hooked by a small dark bit of soil that stood out amidst the mosses, leaves, and fallen Spruce needles and cones which littered the earth.

Tracking and trailing is all about noticing these disturbances in the baseline of the landscape. What sticks out? What is different from the patterns which clothe the land? This scrape was certainly a shift in the pattern and therefore caught my attention. When it did, I looked carefully at the scrape for a moment, took some photos, and then dropped my ruler in the sort of egg shaped exposed soil and stepped back to get a few more photos.
It was at this moment that I heard some rustling from the North of me which sounded like someone was running into the woods. I froze, expecting to encounter a human anxiously running, when I watched a high energy deer come run into view, then stop maybe 5 or 6 m ( 15 – 18 ft) ahead of me, with head bowed and apparently sniffing the air. They themselves quickly appeared to freeze, bracing their limbs. They then gave a quick snort or loud blow of air from their nostrils and then leapt and bounded back towards the way they had come in. This all took maybe 6 seconds to occur. I ended up getting an incredibly blurry photo of the deer heading away from me, but I was too enthralled in the moment to pull out my camera sooner.
Even when the deer had left I remained frozen in place for a couple of seconds in case another deer may show up or if the deer may return, but once I realized there was no return, I quickly left the scene to go retrieve the rest of the tracking crew to share the story and examine the scrape.

Scrapes are created by male White-tailed Deer throughout the year, but mostly during the mating season, which is lovingly called “the rut”. The rut takes place between mid-October through to first week of December, maybe even into January, but I believe the peak is throughout November where I am located in Southern Ontario. During this time female and male deer are leaving scents and sign all over the woods to advertise their intent to mate. While this is an ancient event playing itself out year after year, our knowledge of the details of the rut is always expanding and deepening. This also includes new understandings of what is happening at a deer scrape.

Conventional knowledge tells us the basics; White-tail males will paw at the ground with their fore feet creating a shallow egg shaped to circular depression into the ground. This is essentially the scrape. These scrapes are touched up often by the first buck who created it, but also visited by other deer as they come across them. They are created by young and old bucks (male deer), but it’s about 85% mature males who are “opening” most of the scrapes.
While the buck works the scrape, again scratching away at plant material and revealing the soil beneath, researchers believe he is depositing scent. How? A little bit up from between the digits (toes), on each of the deer legs, there is a gland which secretes a fatty substance which is applied to the substrate with each step the deer takes. This includes these scrapes. From what I am learning, this substance appears to be pretty unique in odour to each individual deer. Some humans (Homo sapiens) can perceive this odour, but personally, I cannot. For deer though, this uniqueness is so pronounced that does can find their fawns by following this scent. Bucks, or male deer, can track females during the rut (mating season) following this scent as well. I think it’s kind of funny to think of the scent coming from between their toes being so important during the rut, but, you know, animals be animaling.
Additionally, though only during the peak of the rut season, after the male is through scratching at the ground, he’ll bring his hind feet up to the scrape, bring his back ankles together and then urinate down his legs and dribble into the scrape. It’s true. Why? Well, the tarsal gland sits on the inside of the leg where the tibia articulates with the metatarsal on the deer’s hind leg. If a deer were a horse, we might say they were located on the hocks. For humans, we would call it the ankle. This gland often named as the most important of the leg glands in that the secretions from the glands and the bacteria they accumulate contain chemical notes which may let other deer know, not only who the deer is, but also the relative health of the deer who left the scent.

Tarsal gland of a White-tailed Deer

Imagine a mature buck standing in place amidst the peak rut. He just started scraping at the ground with his front legs. As he is standing there, he puts his hind legs together at the tarsal glands and then urinates on his legs, dripping through the hairs on the tarsal glands then on to the newly bare soil. Mature bucks do this behaviour more so than other deer during the rut, and that urine mixing with the oily waxy secretions gets pretty powerful.

The long dark hairs at the tarsal glands catch the oily goo produced by tons of the sebaceous glands beneath the hairs. The fatty goo coats the hair and helps hold some of the urine and then the bacteria get in on it and it creates a powerful rank odour.. As the urine runs down the buck’s leg, he then stamps his toes into the ground when they create a scrape.

It’s not only the mature bucks though… old and young, male and female, will all demonstrate this rub urination behaviour. It seems from the literature I have read that perhaps folks once only saw this behaviour in males, but now, especially with a ton of trail camera footage, it seems researchers are noting that females have been doing this behaviour as well. Everyone is leaving scents all around the forest letting everyone else know their getting ready to get down.

We decided to walk on and folks would try and trail the deer I just saw, and to be honest, while I found the first tracks of exactly where the deer stood, crouched and inspecting me, I could not find another track amidst the Goldenrods they had bounded through. I write they because I can’t be sure that this was a male I had seen; I didn’t make out any antlers, and even if I did, some females have antlers as well. While I can’t be certain, the deer lowered their head at me in an “antler threat” display as Stokes calls it (Stokes, 1986), and there was a lot of “big neck energy” in how they moved about.

Some folks in our group are much better at trailing than I am and so they took the lead in trying to follow the deer who had I encountered but the trail was rough going. Soon, some older trails were picked up and followed in hopes to get on some fresh ones again. I have been reading that in the month leading up to the rut there is a lot of deer energy moving across the landscape so these old trails would be common in the area. Scrapes are scraped, urine is sprayed, scent marks are made throughout their territories.

Dark path through the leaves shows the deer trail

While others were on the trail I was off to the edge of the gently sloping forest walking about a meter (~3 ft) away from a steep cliff face looking for an easier way down to the valley below. These cliffs were high limestone walls of the Niagara Escarpment, and definitely deadly if I tried to scale most of it. I had to be focused on my own navigation and was pretty much ignoring a lot of the others who were following the deer trails, but I am grateful they were on those trails. It didn’t take long until the deer’s trails led us to a safe incline we could descend if we followed where they had gone before.
This was a steep path. Clear tracks were visible in the bare soil which had been kicked up on the way down, and as we made our way further, there were some less sketchy terraces where we could easily make out the trail through the leaf litter as the deer had turned up many of the fallen leaves in their descent. This was all highly visible for my untrained trailing eyes and was both grateful for the deer showing us a safe way down, but also for the incline which must have been a factor in compelling the deer to dig into the leaves with more force to stop themselves from tumbling down the hill. This trail was visible all the way to the valley floor where we were met with some scat which appeared wrinkled and moist on the outside but also dried out a bit on the inside. Alastair, a fellow tracker in our crew, had mentioned something he heard at a track and sign evaluation recently from the evaluator, Nate Harvey. Nate had mention that new deer scat has a mucus coating that tends to dry out or disappear after a couple of hours. The scat we found was wetter on the outside, but not like the mucus covered scats I have found in the past. I also remember learning a few years ago from Alexis that if we come across scat that looks fresh, maybe because it looks like it is still covered with mucus, with lines and ridges sort of like raisins, then the scat may not actually be as fresh as we might initially presume it to be. Instead it may be that the scat has froze, then thawed. The moistness would come from the melted snow and the ridges and lines in the scat are from the drying, desiccating action before hand. This is helpful for aging scat, especially in the context of trailing.

Out in a bit of a clearing, just beyond the scat, an awesome discovery was made. There before us was a Basswood (Tilia americana) off to the right of the trail with a long limb stretching out into the path. Dangling from the limb was a long branch that had been broken and hung in the middle of what would be the trail, had it been more defined. The large limb itself hosted a large bright orange gash on the underside where the bark had been violently rubbed away. Below the limb, where it crossed the deer trail we had walked up on, were three scrapes into the earth, where leaves, grasses and forbs had been scratched away and bare soil stood out like a bruise.

These were the signs a buck, and perhaps a couple of them, and when considered all together, signs of the rut. I mentioned the behaviour and purpose of the scrapes above, but I want to touch on a couple more here, namely rubs, which I have encountered often and think I understand, and lick branches, which I have seen less and don’t know as much about.. yet.

Rubs are created when males vigorously rub their antlers up and down against a trunk or limb of a tree scraping off the bark and revealing the brighter pale wood beneath. This rubbing serves a few purposes as the Autumn goes on. First, during the pre-rut period, males rub to help shed the velvety layer of tissue that once enrobed their antlers, nourishing the bone and helping them grow. Triggered by changes in length of daylight (photoperiod) and the increasing testosterone in the male deer’s body, the velvet dies back, sloughs off, and likely becomes itchy or uncomfortable in the process. This flesh that is dying back likely leaves a scent when rubbed against the tree.
Later in the season, bucks also begin to deposit the scent of fatty secretions from a gland in their forehead on to the the bare wood of the rub. These fatty secretions from the forehead gland really start coming out during the peak rut period when the bucks are revisiting previously made rubs of the year, redepositing scent as they go.

The scent sticks around, and the sight of the newly exposed wood highlights the scent. Something really interesting about this sign posting behaviour that has just come to be known by western science is that due to the deer’s ability to see in lowlight and ultraviolet light these rubs appear like glowing patches in the darkening landscape, highlighting these horny message boards for all the deer in the area to check out.
Deer can see colour different than we can, especially in blues and purples in the ultraviolet spectrum (I used to go out tracking all the time in blue jeans. Never Again.) which are more visible around dusk and dawn, which are times of peak activity for the deer! What causes this radiance? It might be terpenes (think of that lovely piney odour) in the sap of the trees, it might be from chemical secretions in the forehead glands, or a combination of both of them. Turns out that this glow in the dark phenomena also occurs in the urine deposited at scrapes during the rut! Just a big glow in the dark party for the deer.

There was also the lick branch. Up until now, all I knew about lick branches was that deer break branches above a scrape and sometimes mouth them a little. Why? I didn’t know. Which deer? Same. Was when important? Still didn’t know. This was something else I had to investigate. I have seen them before, but never really dug into the whys, whos, whens and hows.

I have learned that lick branches aren’t just about the rut. In fact, one book I was reading (Deer, 1995) describes the lick branch as a Spring-Summer social communication hub where identity and status are shared with between bucks. Think of it like sticky notes left on the water cooler. Deer come along through high traffic areas and make a scrape. Remember, scrapes are made throughout the year, they just get more popular come the rut. The buck then grabs a branch hanging out just above head height, which is hanging over the scrape and begins to lick it and mouth it a little, and then rub the glands located in front of their eyes (preorbital glands) all over the branch, and move on. If the buck comes across a branch already in play, then they’ll still leave their scent on it by licking and mouthing the branch, but they’ll also be smelling, and maybe tasting, for other bucks who have come along before them, possibly trying to pick up on who’s who in the area. Folks aren’t sure how specific branches are chosen, but there must be something to it. Maybe the deer just think their cool for some reason? I think of the folks who make videos of cool sticks they find and share them online. Maybe this is the deer’s way of doing the same?

A cool thing we saw on this particular branch, as shown in the second photo of the group of three above, are small marks likely created by the molars of the deer while chewing on the branch. This likely works in some of their scent a little bit more than just licking, helping to hold the scent longer, thus leaving an enduring mark at this site. This is something I had never seen before until this outing, but I’ll certainly be looking from now on.

From this spot we walked on and found a ton more older rubs, a couple of newer ones, some containing fairly fresh tracks, and while unrelated to the rut, my favorite discovery of the day, sign of White-tail browsing thoroughly on a broad patch of Giant Hogweed (Heracleum mantegazzianum). This is going in my list of hazardous plants I have seen deer browse on. A couple others include Poison Ivy (Toxicodendron radicans), Water Hemlock (Cicuta maculata), and Canada Yew (Taxus canadensis). By now I recognize that what might affect us doesn’t seem to bother the deer, but it’s still exciting to see them going hard on plants that would likely kill me or make me very uncomfortable.

Scrapes full of glow in the dark urine, rubs which give off olfactory cues, from both the tree sap and pheromones from forehead glands and they give off visual cues as well through the exposed bright wood by day and luminescence by dusk and dawn, and lick branches wafting scents of saliva and preorbital glands. These all point to layered multisensory complex communication systems in the lead up to possible mating opportunities for the White-tailed Deer. While it may not be as we human animals do, other animals are still chatting away in the forest whether we care to listen to them or not.

To learn more :
Ep. 256 : Apple Scat of Coyotes and Red Fox
Glands on a White-tailed Deer Leg – I copied a lot of my information from that post and used it here as well.
Appearances can be Deceiving by Dan Strickland from The Raven talks about… DEER & MOOSE. The Friends of Algonquin Park, 2003.
Stokes Guide to Animal Tracking and Behaviour by Donald and Lillian Stokes, Little, Brown and Company, 1986.
Field & Stream : The Total Deer Hunter Manual by Scott Bestul & Dave Hurteau. Bonnier, 2013.
Rubs and Scrapes Glow Like Highway Reflectors to a Deer’s Eyes by Lindsay Thomas Jr. 
Deer (The Wildlife Series, Book 3) edited by Duane Gerlach, Sally Atwater & Judith Schnell. Stackpole Books, 1995.
The Deer of North America by Leonard Lee Rue III. Lyons Press, 1997.

Identifying Skeletal Remains of a Common Loon at Saugeen First Nation/Lake Huron

While out tracking with the Earth Tracks Widllife Tracking Apprenticeship along a stretch of beach at Lake Huron at Saugeen First Nation we came across the fairly decayed carcass of a medium sized bird.

The surrounding area was all rocky with some Common Silverweed (Argentina anserina) flowers coming up amidst the corpse, and what looked liked Canada Goldenrods (Solidago canadensis) growing around. A couple meters away there was Eastern White Cedar (Thuja occidentalis) and some Trembling Aspen (Populus tremuloides) stand nearby. The substrate was all pretty rocky on this bit of a spit out into the lake.

Most of the feathers which were touching the ground had begun mouldering and decaying, with the colour fading considerably. We could tell that there was both light and dark feathers, but mostly it seemed like their were lighter feathers on the body. Could it have been a Herring Gull (Larus argentatus)? The overall body size, as observed in this state of decay, was approximately the same size as a Herring Gull, and it would not be strange to find a common bird in this particular area.

I started to look for the skull as the bill would help me indicate the species, and when I found it I realized that Herring Gull wasn’t a correct i.d. for their bills are yellowish with a red spot on the bottom mandible near the distal end. The distal end of the upper mandible also curves downwards. This skull was black with no speacialized spotting though it did look a little worn by weather. There was no downward curved end on the upper mandible either.

 Herring Gulls nares (nostrils) are thin and located midway along the upper mandible, while on the skull we found the nares were pretty large and located closer to the eyes. It was also a relatively large bird skull overall with a broad cranium and long bill. The overall length was about 15.5 cm (6⅛ in) long. Someone guessed perhaps the skull was from a Great Blue Heron (Ardea herodias), but I remembered the skull from a juvenile Great Blue I have at home is a bit longer and narrower overall.
Other possibilities were shot back and forth such as Pileated Woodpecker (kk), Belted Kingfisher (kk), and Black-crowned Night Heron (Nycticorax nycticorax). I think we checked a couple of these in Bird Tracks and Sign by Elbroch, Marks, and Boretos (2001) but none were definitive. It would have to be something to look up a little bit more, but probably at home. This meant taking some bubble wrap from Alastair, wrapping the skull, and gently packing it away in my little lunch container along with the coracoid bones for later examination.

According to Animal Skulls by Mark Elbroch (2006) mature Great Blue Heron skulls range between 19.3 – 22.2 cm (7⅝ – 8¾ in) long overall and 3.3 – 3.7 cm (1¼ – 1½ in) wide. The juvenile skull I have at home is about 18 cm (7⅛ in) long overall and 3.35 cm (1⅜ in) wide. The skull we found was again about 15.5 cm (6⅛ in) long and 4.7 cm (1⅞ in) wide (with a cranium about 3.3 cm tall), being shorter than a Great Blue, but a lot wider making for a more robust skull than the Great Blue overall. It is worth noting that in my examining I did notice some similarities between the skulls.

Both of the skulls were sporting long bills with long wide nares (nostrils). They also both had occipital complexes (bones on the back end of the skull) which protruded well beyond the cranium. The interorbial fenestra (hole in the bone between the eye sockets) was also large in both skulls. But there were also some noticeable differences. The nares on the new skull were longer, and there was a hole which wasn’t present in the Great Blue, on the lower mandible below and behind the formerly mentioned hole.
Additionally, on the top of the newly found skull, there are two symmetrical grooves which run from just posterior of the end of the bill, along the anterior edge of the frontal bone and the rim of the orbits (eye sockets) down to the post-orbital processes (small protrusions behind the eye sockets). These two grooves also each have a small hole in them close to the bill. I didn’t notice these grooves and holes in the field but I did photograph them.

The grooves on the top of the skull along the edge of the frontal bones were never apparent in any of the Night Heron images.

I had originally thought this skull was from a Black-crowned Night Heron, to the degree that at one point I had written a paragraph in this post where I wrote that I was feeling fairly certain. But I couldn’t reconcile a couple of things so I dug deeper and as I did so, I began feeling less and less secure in that identification. I ended up getting into some of the textbooks I have when I came across images of the coracoids of Black-crowned Night Herons and they just didn’t match up. I ended up taking a pause from writing this up and decided to look for a different possible species.

I was just throwing darts at this point. With dozens of tabs open, scrolling through hundreds of photos of skulls, sternums and coracoids, and a growing mess of texts piled around me on every surface within reach of the couch, while fragile delicate bones sat mutely waiting on the cushion next to me waiting to be recognized… I was having a ton of fun but I also wanted to figure out the mystery.

The revelation came in a couple of ways. I was flipping through my own photos from the day of the outing when I noticed I had taken a pretty good photo of the sternum. I noticed first how it wasn’t shaped like a heron of any kind and was oddly sharp looking. I then studied the photo of the synsacrum which was very narrow, laterally compressed compared to many other birds. These were clues I held close as I started flipping through the bone collections of birds at the Idaho Virtual Museum. When I came across the entry for the Common Loon (Gavia immer) things started to click. There were photos of the skull, with the grooves running along the top. The bill shape and nostril lengths looked just right; the sternum (left photo) had that same sharp look and the synsacrum (right photo) looked right on as well.

I visited another source, Skullsite.com (developed by The Experimental Zoology Group of Wageningen University). Their measurements for Common Loon are:

Length : 164 mm
Length (cranium) : 66 mm
Width (cranium) : 49 mm
Height (cranium) : 38 mm

The skull we found:
Length : 155 mm (6⅛ in)
Length (cranium) : 64 mm
Width (cranium) : 47 mm (1⅞ in)
Height (cranium) : 33 mm (~1¼ in)

Now, I am again feeling pretty secure about this identification but I wrote this before in regards to the Black-crowned Night Heron. But what about the coracoids? Do they fit under close inspection?

Many folks reading this post will remember that I am pretty excited about learning to identify bird carcasses based on the shape and size of coracoids. I know this is a very tricky practice, and often we can only get down to family groups, but even that would help differentiate between a heron, a gull, and a goose. If you want to read more about coracoids check these out (1)(2).

For a quick review of how to measure a coracoid:
First, measure the greatest length (GL) of the coracoid. The GL is determined by determining the two most opposite points and measuring from there. It’s not about trying to find the middle of the base or from a specific location on the bone, but more so just figuring out the greatest length that the bone can be measured and using that number.
Second I measure the length of the medial side (Lm). This requires a bit more precision. First you’ve got to figure out which is the side of the coracoid which would be facing towards the midline of the body of the bird. This is the medial side (medial just means “towards the middle”). Next find the bottom inside “corner” of the bone. This is called the “internal distal angle” (located on the second image with a red asterisk). Measure from the point where the asterisk is, again, the internal distal angle, all the way up to the top of the bone. This measurement is your Lm.
Basal breadth (Bb) is a bit simpler. Just measure the distance between widest points of the bone at the base. That’s it.
For the last one, the breadth of the articular facet (Bf), you’ve got to locate the shallow groove where the bottom of the coracoid would articulate (meet or join) with the sternum. This is called the articular facet or the sternal facet (I used the phrase sternal facet in my previous post on coracoids). Measure the length of this facet. What’s a facet? A facet is the smooth area where two bones come together, often bordered by ridges or protrusions which allow the surfaces to fit together snugly without shifting or slipping beyond the functional limits of the joint.


Left and right coracoids from the skeletal remains of the then unknown bird. ~7 cm (2¾” in) long.

Here are the measurements I got from the coracoids, right and left:

Greatest length :
R :
73 mm (2⅞ in)
L :
71 mm (2¾ in)

Length of the medial side :
R :
61 mm (2⅜ in)
L :
58 mm (2¼ in)

Basel breadth :
R :
39 mm (~1½ in)
L :
38 mm (~1½ in)

Breadth of the articular facet :
R :
32 mm (~1¼ in)
L :
31 mm (~1¼ in)

According to Avian Osteology by Filbert, Martin, Savage (1996) the measurements for the Common Loon are :
Length Range : 67 – 79 mm
Breadth Range : 28 – 37 mm

Now I am unsure which breadth is being referred to in the range described above, but the breadth of the articular facet would be a match. They also write that the procoracoid process strongly hooked which can be seen in the photo above, especially on the right. They mentioned a small opening at the base of the procoracoid process as well, which is evident in the hand but not shown in the photo above. I wish I could find more information to support the coracoid ID, but that might have to wait.

Image of a mounted Common Loon skeleton with coracoids in situ, anchored into the top of the sternum and bracing the humerus. Note the articulation with the furcula (“wish bone”) at the head of the coracoid. From https://sketchfab.com/3d-models/mounted-loon-skeleton-a784da638bf4450e8703819a1d14f2cb

The last thing I needed to confirm/understand/look up was those grooves in the skull above the eyes. It is often remarked that the skull can teach us more about the natural history and ecology of an animal than any other part of the body so I wanted to figure out what this characteristic was all about and what we can learn from it?

Turns out this groove is not unique to Loons, but instead may be common in other birds such as petrels, penguins, albatrosses, gulls and terns. They are sometimes called the supraorbital (“above eye”) grooves. Why would these birds share these supraorbital grooves? What do they have in common? A life by or on the sea – on saltwater! With all of the fish they eat, and water they have to drink, these birds need to expel the salt before it builds up too much and takes a toll on their systems. These grooves are actually spots where a salt-secreting gland which acts similar to kidneys sits and helps the birds expel salt from their bodies. The salt moves through these glands and then drips onto the bill where it can then drip away. For petrels, the gland drips into the nasal passages where the birds can then sneeze out the excess salt! I think this is pretty damn cool, and weird cool facts help me remember stuff better. Thank you weird salt glands!

There was so much else I could have written about from our outing; Northern Flicker (Colaptes auratus) kill site, the unknown pellets we found, the other bird skull we found, the Bald Eagle (Haliaetus leucocephalus) feathers, the Common Grackle (Quiscalus quiscula) tracks – all this within the first two hours! But I wanted to dig deep into this one find and try to learn more. I hope you all learned something too. Big thanks to the Common Loon, to Saugeen First Nation, to all of the authors who put in the time to write these books and make these websites so we can learn, and to Alexis Burnett and all who came out to learn and track together. I’m stoked to get to be a part of it.

To learn more :
Animal Skulls by Mark Elbroch. Stackpole Books, 2006.
Skullsite.com page on Nictocorax nictocorax (run by The Experimental Zoology Group of Wageningen University)
3-D image of Black-crowned Night Heron
Idaho Virtual Museum bone collections
Idado Virtual Museum 3-D image of Common Loon skull
Two Coracoid Bones blog post
Two More Coracoids blog post
Avian Osteology by B. Miles Filbert, Carry D. Martin, Howard G. Savage. Missouri Archaeological Society, Inc., 1996.
Mounted Common Loon skeleton in 3-D from RISD Nature Lab
Manual of Ornithology by Noble S. Proctor & Patrick J Lynch. Yale University Press, 1998.

Early Days In The Lives of White-tailed Deer Fawns

While out at Dunby rd section of the Bruce Trail with the Earth Tracks tracking apprenticeship, I was walking slowly under some White Pines (Pinus strobus) looking for owl pellets. We had found some in that same spot a couple years before and I was hoping to find some again. At one point I lifted my foot to take a step when there was a sudden movement directly under where my foot was about to land. Something large and pale brown jostled about and I quickly called out and stumbled back. It took me half a second to realize that the large pale brown shape that was moving away from me was a White-tailed Deer fawn (Odocoileus virginianus). I started looking around quickly, out to my tracking companions and rapidly back to the fawn. I was awestruck and needed to see if anyone else had seen the fawn. Eventually someone else saw the young deer and we managed to get everyone’s attention. Some folks even crept up to the fawn’s new hiding spot and got a couple photos. I tried climbing a nearby tree in hopes to get a better view without disturbing the newborn, but the young deer took off through a fence and up a hill by the time I was stable enough in the tree to turn around.

Fawn deer bed, which, if I remember correctly, measured 35.5 × 20.3 cm (14 x 8 in).

For those who are new to all of this, a fawn is generally used these days to imply a young deer of any deer species. The word originates from the Latin fetus, which you probably recognize to mean something akin to offspring or new life. The word transformed from the Latin into Old French and Anglo-French faon or feon meaning a young animal of any kind, then on to Modern English, as fawn. But since around the 15th century the word fawn has typically implied a young deer.

Does (female deer) gestation period is about 200 days giving birth in May or June depending on her mating success in the Autumn of the year before. When the doe is pregnant for the first time she will likely give birth to a single fawn but in subsequent years she will likely give birth to twins. A female deer has In writing this post I learned that in some populations of White-tails, up to 22% of twins will have two different fathers. Multiple paternity, the fathering of individuals within a single litter, is also known in other species as well such as Deer Mice (Peromyscus maniculatus), Black Bears (Ursus americanus) and Opossums (Didelphis virginiana). I have heard about it for some birds, but I don’t remember where from. It’s pretty cool. I found a blog post from the blog Backyard Biology and I am just going to pull a quote from them as they wrote it up so succinctly.

Unlike humans, deer have a two-horned uterus, and typically, each ovary contributes an egg which is fertilized in one of the horns, giving rise to an embryo that develops in that horn — thus, most twin fawns are likely fraternal. The incidence of identical twins is very small, as it is in humans.

However, that doesn’t mean that they are full brothers, the result of eggs fertilized by the same sperm.  Using a molecular genetic analysis, studies on deer herds in Michigan found that 22-26% of twin fawns actually had different fathers (the percentage is higher in penned deer herds than free-ranging), and that the largest, oldest bucks in the herd do not always father all of the offspring. In these herds, 18% of yearlings, and 50% of 2 year-old bucks were also successful in fathering offspring.

I love when we find examples in the world that counter the paradigms humans cling to as a supposed baseline. Go Nature!

Just before the pregnant doe is ready to give birth, the yearling young from the previous Spring will be driven away so the doe can give birth in seclusion. This behaviour is possible done as an attempt to ensure proper imprinting on mom instead of some other deer who may not be so inclined to care for the new fawns.
She’ll find a spot and lay down, get up and pace, lay down again, pace, until the babies are ready to come. I have read in two texts that White-tail moms can have a labour of a half hour, or over 12 hours. That is a huge disparity. I am unsure still about how long the labour of a White-tail is but I am wondering if there was something else implied. Perhaps the labour, the whole process, takes about 12 hours, but the actual birthing is over in about a half hour? That would explain those vastly different accounts.

Photo of second fawn we saw taken by Alexis Burnett.

When the fawns are born they may weigh between 1.8 – 4.5 kg. Twins are generally smaller than singletons, and males are usually slightly heavier than females. They are born with three or four cheek teeth. The third premolar, called P3, has three cusps (those spikey points at the tops of the teeth). If a fourth tooth is present, it is the first molar, M1. A fifth tooth, M2, will emerge within six months of birth, and a sixth tooth, another molar, M3, will emerge before reaching 1.5 years old. If you come across a White-tailed mandible with less than six teeth, it was from a fawn.

Mary Holland writes in her book “Naturally Curious” that mother deer will consume all of the afterbirth and fetal membranes. She then licks the fawn, head to toe, focusing on the anus, to remove any scent and likely as part of a bonding process between mother and fawn. With all of the afterbirth gone and the coat revealed, fawns of White-tails can be seen with a beautiful chestnut brown on their upper back which fades to a pale, almost orangey brown and finally to white at their belly. According to my research it seems like hairs which make up these white spots are only white at the tips of the individual hairs, while they are the same reddish chestnut brown found on the rest of their Summer pelage. The white tips wear away by the end of Summer and the fawns coats appear similar to adults. All of this is dappled with white spots. Despite these bright beautiful colours the fawns are amazing at hiding amidst tall green grasses and forbs.

Newborn fawns spend a good chunk of their early life curled up in their beds though they can walk within minutes of being born. Leonard Lee Rue writes that it is up to 96% of the time, though this is interspersed with getting up and finding a new bed, up to 6 times a day. He writes that they don’t usually go more than 6 m (20 ft) away from their previous bed when settling into a new one. The twin fawns don’t bed together. In fact the doe will keep them separate intentionally, likely to ensure their survival in case one of the fawns is taken by a predator such as a Coyotes (Canis latrans). If a week old fawn is disturbed they can readily run to try and evade a predator, but the newborns are often quick to drop when a predator comes close.

About 7 years ago during an apprenticeship outing, at on the beach of Lake Huron at Saugeen First Nation territory, I came across a fawn track in the mud on a small peninsula out into the water. The track was approximately 3 cm (just over 1⅛ in). I have included the photo below.

~3 cm (just over 1⅛ in) fawn track.

The fawns can stand and may begin to nurse very shortly after their births. They are nursed by the doe between 4 – 6 times a day at around 4 – 10 minutes a turn. Shortly after birth they drink about 60 – 118 ml of milk every four hours. By the time they are a week old, the fawns are drinking nearly 900 ml a day. Deer milk is richer than the milk of domestic cattle (Bos taurus). For deer on Turtle Island/North America, milk protein averages at about 7 or 8 % compared to the 3.5% in domestic cows. This is incredible and I wonder at the difference in food sources that nourish the deer versus the domesticated feed which we give cattle? Would wild cattle have better milk if they ate different food? Are they malnourished? A sign that a fawn is malnourished is when their ears become slightly twisted. But it seems like as soon as they fawns are eating well again, their ears will straighten out. A good sign to look for when encountering a fawn in the future. Fawns will start eating green vegetation at around three weeks of age, and are weaned by about four months.

I have had the chance to see a couple of fawns in my life, all by chance. It is such a gift to be able to see the young of another animal in their natural habitats doing whatever it is the young of the species are supposed to be doing. I am always grateful for the experiences we get on these tracking outings and for all the amazing wildlife encounters we have while we’re out. Thanks to all who were out with us there, including the humans, the deer, and everyone else.

To learn more :
Natural History of Canadian Mammals by Donna Naughton. Canadian Museum of Nature and University of Toronto Press, 2012.
Paternity Assignment for White-Tailed Deer (Odocoileus virginianus): Mating across Age Classes and Multiple Paternity by Anna Bess Sorin. Journal of Mammalogy, Volume 85, Issue 2, 12 April 2004.
Deer (The Wildlife Series, Book 3) edited by Duane Gerlach, Sally Atwater & Judith Schnell. Stackpole Books, 1995.
The Deer of North America by Leonard Lee Rue III. Lyons Press, 1997.

Determining Direction of Travel on a Fisher Trail

“Which way them critters goin’?” my friend Dani would call out every time I mentioned I was leaving the house to go tracking, and to this day it can be really tricky, especially in deep snow. For me it takes a good amount of analysis from the moment we encounter a trail, and all throughout as many animals will backtrack, circle round, walk on older trails, walk in another animals trail, or even in their own older trails. There are many points when trailing an animal that the direction of travel can be confused or undetectable entirely. But instead of giving up, we have processes that can help us, especially when they are used in combination over longer stretches of the trail.

For this exploration in determining the direction of travel (DOT), I’ll use a snowed in Fisher (Pekania pennanti) trail we encountered during an Earth Tracks Tracking Apprenticeship outing at Bognor Marsh, near Meaford, Ontario as an example. It was a faint trail, mostly snowed in, but the impressions were visible at the right angles, as long as they hadn’t been blown away in the wind.

Shape and angle of the impression

Rounded solid edge would indicate the direction of travel (DOT).

It is certainly hard to see in the photos, and believe me when I write that it was also hard to see in person. At some spots these tracks were invisible to see entirely, and some you had to look at the trail in just the right angles to see the faint snowed in trail. But we took the time as we wanted to fore track the Fisher, to follow them in the direction they were going in, rather than back track and go in the direction which they had been coming from.

When we first came up to the Fisher trail we quickly examined the faint impressions to look for the shape of the impressions. I wanted to see if there was a broader rounded edge and a narrower tapering edge of each track. The broader, more solid edge of the track would be where the toes are, and this edge tends to be deeper than the heel or back of the track, as I have noticed that most wild animals tend to be a bit more “toe heavy” and their feet sink in at the front a bit more. The heels however do not always register in the track as deeply and tend to taper in appearance and depth. So in the photograph above and the poorly drawn image on the right would both indicate that the Fisher’s DOT is towards the top of the screen.

Look for the toes

Even though we didn’t find any clear tracks on this particular trail, looking for impressions of the toes at the front of the track is very useful technique for discerning the DOT. Deep incisions into deep snow are often angled in such a way that we can’t see the track floor where the actual imprint sits. We can still use this track to determine the DOT by digging away a few layers of snow, or taking off our gloves and using our bare hands to feel the track. By doing this you can sometimes feel the number of toes, or the ridges between the toes like the cleave between toes 3 and 4 of a deer.

Behaviour like turns and stops + Look for the track pattern

As we carried on the Fisher trail we encountered a couple of times where the Fisher slowed down and investigated. We couldn’t tell what the Fisher was concerned with but we could tell that they slowed and turned. One way we could tell this was by looking at the track pattern left in the snow. In the photo above, the Fisher slowed to a walking gait as they made their way up from the bottom right of the image. Then their trail arced back towards the bottom left of the photo before quickly continuing on their trail in a loping gait towards the top of the image, leaving behind quicker 3×4 and 4×4 track patterns.
We can look at the track patterns and consider the movements of the animal by comparing with what we know about Mustelids (the Weasel family to which Fishers belong) and by thinking of ourselves. Weasels and humans tend to slow down when when investigating something. We will walk to look carefully, and only when we are ready to move on will we jump back into high gear and take off again. This change of gait, from a slow exploratory walk to a faster 3×4 loping gait used by Fishers to cover ground, can be seen as an additional tell of the DOT in the trail. So once we see the DOT we can recognize that the track patterns left behind indicate that the animal moving from the bottom of the image, across and arcing to the left, then up the image and out of the frame.

If we were to imagine the Fisher or ourselves coming from the opposite direction, from the top of the image down towards the bottom, we could see that the animal is moving quickly because of the track pattern indicating a faster gait. They then stop suddenly, without an apparent disturbance to the snow, leaving no slide from slipping, no thrown debris from the forward momentum. The trail would then have to be interpreted as the Fisher walking steadily backwards in an arcing trail until out of the frame on the lower right. While I have seen a Mink (Neogale vison) walking backwards to avoid being noticed, this behaviour is pretty rare and unlikely. Instead we have to assume the more likely storyline, while putting the pieces together in a logical way, noting the behaviour of the Fisher. If we do this we can see that their DOT was towards the top of the image.

Pointing with feet

Pointing with feet implies the times when an animal is looking in a specific direction, perhaps to see what is going on, or to listen, or perhaps even to browse on some nearby shrub. The animal will put out a front foot in the direction that they are looking. The track may be very lightly impressed in the snow. The track will appear out of baseline, out of the regular rhythm of the regular track pattern left behind, indicating that something happened here and it is worth checking out. This is also a moment to determine the DOT because the front foot, either left or right, will be facing forwards towards the DOT but perhaps slightly to the side.

I see this a lot with ungulates such as White-tailed Deer (Odocoileus virginanus) and Moose (Alces alces), but have also see this with Lynx (Lynx canadensis) and Coyotes (Canis latrans). I realized I didn’t get any photos of this behaviour, but it could be lumped with the heading above.

Debris

As mentioned above, another good way to determine DOT is to look for debris in the trail, especially snow kicked up at the front of a track. I was discussing this characteristic with a student this Winter who was quick to demonstrate that snow will be pushed out of a track to their rear, pushed behind them as they lift their foot as result of forward propulsion. They then replicated this by sticking their boot into the snow in a mock step and then intentionally dragging snow out behind them. My response was to point something out ahead of them, something too small to see from where they were standing. They had to walk over to the fictional point of interest, now distracted from the point they were trying to make. When they have walked over to take a look, distracted from the point they had just made, I got them to stop, turn around and look at their trail. Most of the snow had piled at the front of their tracks where they lifted their boots out of the snow. This was pretty convincing.

Now, snow or other substrates can be thrown back behind a track when an animal, including humans, are moving at a faster pace, pushing off of the ground with a forceful step, but I only remember seeing this when someone is starting to move in a run. When I think of it now, it makes me want to go out and try some experiments with a tracking class and see what we can figure out. Will more snow be thrown backwards as more force is being used to propel a body forward?

“When in doubt, track it out”

Once, we were on a Red Fox (Vulpes vulpes) trail for four hours before seeing a sign of the DOT. The snow was too deep to see toes in the tracks, and when we reached in, we still couldn’t make it out. We followed the trail for the morning and then stopped for lunch. It was only after lunch that we encountered a stretch of the trail where the fox had jumped over a log, knocking over some snow which had piled up on the log, that we were able to tell which way the fox was going. We looked to the snow to tell which way it had been knocked over to determine the DOT.

I share this story because sometimes it’s truly difficult to figure out the direction of travel. I have been challenged over and over, humbled so many times by different animals moving through varied substrates at multiple angles of slope. It really comes down to taking our time to sort it out with each new trail we encounter. We can use the tools described above, and likely many more I don’t know about yet, but this takes time in the field and patience with the trail.

“When in doubt, track it out.” Persist in the journey. Focus on the baseline and any changes in the track patterns which may indicate behaviours, and then feel out those behaviours to see if it feels like it would fit the mechanics of the animals body. Look for the deepest part of the track and for debris kicked up at the front of the track. And if you still can’t sort it out, keep going.

To learn more :
Mammal Tracks and Sign by Mark Elbroch and Casey McFarland. Stackpole Books, 2019.
When the Snow Gets Deep – blog post by Linda J. Spielman

White-tailed Deer feeding sign at Kinghurst

Recently, at a TCNA “tracker tuesday” call, there was a challenge proposed: on your next tracking outing, practice following the deer or the rabbits and see if you can find 10 plants which they fed on. For me in my area, the deer would be White-tailed Deer (Odocoileus virginianus) and the rabbits would be Eastern Cottontails (Sylvilagus floridanus). While I have been observing the Cottontails loosely at work with my students, for this tracking outing with the Earth Tracks Wildlife Tracking Apprenticeship, we focused on the White-tails.

Winter food finding in Southern Ontario is tough for all species. Not only is there a lot of snow on the ground, many of the common forbs which the Deer consume are long dead and the remaining and accessible plants are mostly tougher woodier species which tend to be harder on the teeth and harder to digest. In addition to these impediments White-tailed Deer prefer a mixed bag of food sources. They tend to seek out a variety of mixed forage. While occupying smaller “yards” or Winter territories the White-tails often have less diversity of choice. While their Spring, Summer, and Fall diets are of a more cosmopolitan variety, in Winter they are forced to live off less.

It’s important to consider not only what the deer are eating, but also how. Let’s remember the basics. White-tailed Deer bite off the ends of twigs with their incisors, the teeth at the very front of the mouth. We may think of our own incisors at the top and bottom in the front of our mouths, but when it comes to the Deer they only have incisors on the bottom mandibles. This is also true for a few other species as well, such as everyone else in the family Cervidae (including deer, Moose, Caribou, Reindeer), members of the families Giraffidae (Giraffes, etc), and the family Bovidae (Cows, goats, sheep, etc). All members of these families have no incisors in the cranium. Instead, when they bite those twig ends off they rip them off by grasping the twig end between their lower incisors and the hard palate above. Some other species, such as members of the Rodentia and Lagomorpha orders, cleanly slice twig ends off, but for these no-upper-incisor-having species, it’s often a ragged rough hewn rip. See if you can see this in the photos below.

In “Deer (The Wildlife Series, Book 3)” (Stackpole Books, 1995), Dietland Muller-Schwarze wrote that Deer, like other ungulates, have quite a lot of circumvallate papillae (one type of many bumpy structures on the tongue that gives it the rough texture). In Humans (Homo sapiens), we have between 8-12 of these large structures near the back of our tongue and each structure holds about 100 taste buds. These taste buds on the circumvallate papillae are especially sensitive to bitter tastes. Muller-Schwarze writes about how Deer will commonly spit out bitter forage when they come across it, but for me, this begs the question of how bitter is too bitter for a Deer? Some of the plants described above and below can be pretty bitter tasting to me but I am curious about the time of year when bitterness is most expressed in a plant? I think of bitter annuals in early Spring like some of the Mints (Lamiaceae) and Mustards (Brassicaceae), how often to the Deer munch on these? Perhaps we’ll need to keep an eye out in the Spring to find out.

Lucky for the Deer at Kinghurst, there is a variety of fine forage for them in the Winter. Here I will share some of the variety of plants which we observed feeding sign on, listed in the order in which we came across them. I would love to trail the deer in other areas in Southern Ontario and see what they forage on there. Next time..

 

 

1) Alternate-leaved Dogwood (Cornus alternifolia)

The Alternate-leaved Dogwood is also known as Green Osier and Pagoda Dogwood. I think Pergola would be a better name as a pagoda is multistoried and closed on the sides, while a pergola is single storied, and open, more closely resembling the growth form of this outlier in the Cornus genera. I write outlier because the Alternate-leaved Dogwood is just that, alternately leaved and branched, while the rest of the Cornus are opposite branched or whorled. White-tailed Deer tend to consume both the leaves and the twigs.
C. alternifolia is plentiful at Kinghurst. They tend to grow as an understory shrub in open woods, ravine slopes and hillsides, in forests with mature canopy species such as Sugar Maple, Eastern Hemlock (Tsuga canadensis), and Yellow Birch (Betula alleghaniensis). There are the places where the White-tail tend to hang out.

 

 

2) White Ash (Fraxinus americana)

Common species in the upland forested landscape which I tend to see coming up quickly in areas where other coniferous trees have come down, leaving a gap in the canopy. Most of the larger White Ash and Black Ash (Fraxinus nigra) we found were riddled with Emerald Ash Borer (Agrilus planipennis or EAB) sign and epicormic shoots, but the younger ones the deer were hitting, not so much. We did find one massive old White Ash with a Winter Porcupine (Erethizon dorsatum) den in the base, with the Porcupine huddled up inside. I did not see any sign of EAB on this big one and wonder if they are resistant somehow? If this individual tree is resistant somehow, I hope they are a pistilate or seed flower bearing individual (White Ash trees are either pollen flower bearers or seed flower bearers) and survive to spread viable seed with that same possible EAB resistance. We noticed lots of feeding sign adjacent to the den, but this was Porky sign with 45°ish cuts at the end rather than the ragged cuts the deer tended to leave behind.

 

 

3) Eastern White Cedar (Thuja occidentalis)

Eastern White Cedar is the one of the most important food plant in the Northern woods; one of the only green plants in the NorthEast which can sustain deer in the critical part of Winter. Aside from being an essential food source, White Cedar also provides good thermal cover in the Winter months similar to Eastern Hemlock (Tsuga canadensis). The White Cedar grow in tight groves helping keep the snow cover below shallower than surrounding open forests.

As White-tailed Deer move through White Cedar groves they tend to feed on all the green leaves from the lower branches within reach, often creating visible, generally uniform horizontal browse lines. These browse lines are a clear indicator of White-tailed Deer population in a given area.

 

 

4) Black Locust (Robinia pseudoacacia)

Black Locust is a tree that I have read described as a non-native invasive species which chokes out local tree populations. I have seen this native to the faraway distant (note the sarcasm) mountain tops of Pennsylvania to be an early colonizer of meadows and preventing erosion by stabilizing soil with an extensive root system. The bees love the beautiful and tasty flowers and it seems the White-tailed Deer appreciate the young shoots for Winter browse. The Black Locust was once planted for the valuable wood and also as a beautiful ornamental with their amazing dangling, pungent flowers. While the thorns may be irritating, they have developed on the tree to prevent too much herbivory by from the Deer while still giving something in the way of a good food. If only we could all learn good boundary making like this plant.

I noticed many of the individual Black Locust trees growing at Kinghurst were growing in open canopied clearings along the edge of the pine plantations, and this makes sense as they are intolerant of shade. I would imagine as more mature trees come down in that forest, more Black Locust will be coming up. They can do this quite easily, and they don’t need seeds. The Black Locust commonly spreads by sending up “ramets” or shoots from underground runners. If the Deer did consume a new shoot all the way to the soil, then the root would just send up another one.

 

 

5) White Pine (Pinus strobus)

For all it’s ubiquity, I don’t believe I have ever noticed White Pine being browsed by the Deer until this occurrence. I know this is a common occurrence detailed in the literature I have read, but I had not seen it before. I appreciate this assignment as I am now looking at this pretty common species in new light and noticing something that has likely been there forever, but is new to me. The White Pines I encounter also seem to be very large and in mature forests where the White-tails cannot reach the lowest branches but I am going to have to pay a lot more attention now just in case.

 

 

6) Common Blackberry (Rubus allegheniensis)

Similar to the Black Locust above, the Blackberry has a perennial root which sends up shoots. Instead of ramets, they are called canes which have a two year life span. Also similar to the Locust, Blackberry is intolerant of shade, I guess I am seeing a pattern. The Locust, and the Blackberry were both growing at the edge of the Pine plantation. This lets me know that the area is likely pretty sunny and that the Deer are moving through there.

White tailed Deer population thrive in edge spaces. The edges of a White Pine plantation, the edges of a field, the edges where suburban homes meet the green corridor protecting the creek. These are also prime places for the disturbance adapted plants such as Blackberry and the Locust and a host of other forbs. These help create a rich and varied diet for the Deer.

 

 

7) Red-osier Dogwood (Cornus sericea)

The Red-osier has a broad range, covering the boreal and temperate forest regions across the continent, so of course the White-tailed Deer, with a similarly broad range will encounter this shrub. Identified by the red bark on twigs and upper branches, a red which appears to grow redder when the Winter season starts to consider the shift to Spring. Often growing in wetter areas, good to look out for to know where the water might be in a snow covered landscape.
This shrub has taught me a lot over the years. So much so, that I purposely go check out the C. sericea when I am out tracking because it is very likely I will find sign of deer browse. I don’t know if it is the ubiquity of the plant or the blazing red which draw the deer in, but they appear to like this one a lot. I have seen some Red-osiers hit so hard they look as if a bonzai beginner just learned how to use their sheers and got snip happy, stunted and oddly growing, though without a clean cut. This is a good one to look out for on the land when wondering where the deer may be hanging out.

 

 

8) Black Cherry (Prunus serotina)

I associate many of the included species with medicinal action in the human body, and I wonder about these same actions with the Deer? I recognize we have different physiologies, but could they work similarly in an ungulate body as they do in a primate body? And if there is similar action medicinally, what about toxins? I have found White-tailed Deer browse on deadly poisonous Water Hemlock (Cicuta maculata) in the past yet did not find a dead Deer beside the plant. Same with Canada Yew (Taxus canadensis); feeding sign, but no dead animal. Do the Deer feed on the foliage of the Black Cherry or just the twigs? The leaves are full of cyanide and could be pretty harmful but perhaps the Deer have more suitable browse in the months when the Cherry leaves are present? I have also read that the twigs have cyanide present, but perhaps not as much as the leaves? Or maybe it just doesn’t bother the Deer at all and they’ll just eat what they want?

 

 

9) Sugar Maple (Acer saccharum)

Sugar Maple is a tree I could also get down with munching on. While a little bit bitter from the chlorophyll, the inner cambium still tastes pretty good. Yes, I have tried it. I have also eaten some buds on Sugar Maple in the past and I remember thinking they were palatable. Something I have also learned through the apprenticeship program is to identify Sugar Maples by looking at their the buds at the end of the branches, also called “terminal buds” (which happens to be the name of my nature gang). Sugar Maple terminal buds tend to narrow towards the tips and are more pointed and sharp feeling than, say, a Red Maple (Acer rubrum), which has rounder terminal buds. So the mnemonic “sugar sharp” can help us remember the Sugar Maples, and “red round” for the Red Maples.

 

10) Wild Grape (Vitis sp.)

A couple of weeks ago during an apprenticeship meet up at Dunby road, we had found feeding sign from White-tailed Deer on some feral Apples (Malus domestica) and some Grape (Vitis sp.) vines. These were very fresh and clear to see. Now fast forward to the outing at Kinghurst, where we struggled to find feeding sign on Grape for quite a while. I was excited when we found it.

I love eating the forked tendrils which grow at the ends of the Grape vines as they are crunchy similar to a Japanese Knotweed (Reynoutria japonica) have a slightly sour and bright flavour. I have eaten them on their own and in salads. I bet the Deer would also go for them in the Spring. But do they eat the leaves as well?

 

 

11) Hop Hornbeam (Ostrya viriginiana)

I had never seen feeding sign on Hop Hornbeam from an ungulate until this outing. I have seen individual pouches from the hop-like seed clusters opened by Eastern Chipmunks (Tamias striatus) but never had I seen the browsing on the twigs. Since then though, I have seen more ungulate feeding sign, namely Moose (Alces alces) up in Algonquin Park. I wonder if, like Porcupines (Erethizon dorsatum), Deer have specific browse that they tend to have individual preferences for? Do some Deer like the Hornbeam while most don’t find it palatable? Or is it just a case of my not seeing it before as most of the Hornbeams I notice are older, taller and have little to no lower branches within reach of the Deer to browse on?

 

 

12) American Beech (Fagus grandifolia)

American Beech seeds are tasty. I have found them hard to gather as a lot of seed cases turn out empty, and a bit tedious to collect so many tiny Beech “nuts” even when the cases are full. It takes a long time to gather even a few seeds. I remember once gathering about a cup of seeds with friends a few years back and between the three of us it took about an hour. I wonder if the Deer can smell it when the seed cases are full versus when they are empty? As for the twig browse, there was only a bit of browse at Kinghurst, but again, in Algonquin the Moose were hitting it pretty hard in some areas.

and one more bonus conundrum…

 

13) Digging?

I have seen sign of deer digging through the snow to access ferns and acorns before, but in this case there were no Oaks (Quercus sp.) or acorns around that I know of, and I couldn’t see much in the snowy debris of ferns which had been consumed. We were wondering if the deer were searching out roots of some kind, or perhaps they were feeding on some green shoots of grass, which however rare or unusual, has been observed in the past. Because I cannot determine exactly what the deer were after, I have included this as a bonus find, to be observed further in the future.

To learn more :
The Deer of North America by Leonard Lee Rue III. Lyons Press, 1997.
Trees of the Carolinian Forest by Gerry Waldron. Boston Mills Press, 2003.
Animal Skulls by Mark Elbroch. Stackpole Books, 2006.
Deer (The Wildlife Series, Book 3) edited by Duane Gerlach, Sally Atwater & Judith Schnell. Stackpole Books, 1995.

More of the Scoop on Ruminant Poop (and Other Digestive Specialities)

This February 2025, while out with the Tracking Apprenticeship Group near Bell’s Lake, Grey County, we started using some terms for which I’m not totally clear of the meaning. I’d like to unpack them and share my learning here with you.

The words are rumen, cecal scat, ruminant and ungulate.

After a quick look up, I learn that an ungulate is simply an animal that has hooves. Horses, cows, deer and moose are all examples of ungulates.

While all ruminants are ungulates, not all ungulates are ruminants.

According to the Merriam-Webster Dictionary, ruminants are animals where food is ingested, held in the rumen, and then brought back up into the mouth to be chewed again. More specifically, they are herbivorous, even-toed, hoofed mammals (suborder Ruminantia and Tylopoda) that have complex 3- or 4-chambered stomachs. Examples of wild mammals in Ontario that are ruminants include deer, moose, elk, and caribou.

Moose are ruminants

When ruminants eat, they ingest their browse and after a very quick chew it is held in their rumen (the largest of their stomachs) where the cellulose fibers begin to be broken down by bacteria through fermentation. This material is then formed into balls (the cud) in the reticulum, which the animal chews a second time before swallowing, sending it down into the rest of the stomach for further digestion.

So the rumen is basically a fermentation tank for plant fibers. It makes sense then that we often find the contents of rumen in the prey remains from deer and moose; it is the largest chamber of the stomach and holds the biggest volume in proportion to the rest of their digestive tract (up to five gallons in a mature domestic cow). When a carnivore is consuming a ruminant, there is a lot of fluid and plant fibers in the rumen that they cannot digest and are left as waste.

Ruminants and most other animals including humans, have another stomach chamber that also helps break down tough plant fibers and this is called the caecum (cecum). It is the final chamber before waste is excreted. Like the rumen, the caecum allows for fermentation and nutrient and water absorption.

Learning how ruminants digest their food makes me wonder about porcupines, snowshoe hare and beaver.

According to a research paper from the University of Wisconsin, Stevens Point, beavers do have a caecum, close to the end of their digestive tract like ruminants, but they don’t have a rumen, and don’t chew the cud. Like rabbits and hare, however, they accomplish the task of breaking down cellulose and other plant fibers by being coprophagic. Coprophagy is when an animal passes stool after quickly consuming their food, and then re-ingests it in a safer restful situation where it can be chewed up more finely to allow for better digestion. It kind of serves the same function the rumen and reticulum. According to Dr. Uldis Roze, Professor Emeritus, in the Department of Biology, Queens College, porcupines, who have a relatively larger caecum, are generally not considered to be coprophagic.

Snowshoe hare are coprophagic

My final question relates to the caecal scat we often find from grouse. Do they have a caecum like ruminant mammals? Why do they have two different scats (the dry, fibrous kind and the goopy caecal kind (that looks kind of like caramel).

From what I was able to find online, most birds have two caeca, called cecal pouches. This division of the caecum is an adaptation to aid in their ability to fly.

While I did not find specific information on the cecal scats of grouse, I was able to find information relating to domestic hens, which are similar. The cecal sacs are emptied by both chickens and grouse when they become full of indigestible plant material in order to make room for other material as the birds eat. In the ruminants discussed earlier, the caecal contents are mixed in the regular faeces produced by the animal. In birds, they are excreted separately.

Ruffed grouse

Dry and caecal grouse scat

I am pleased to have learned more about these digestive processes and hope it is new learning to some of you as well. It is only scratching the surface, but when it comes to digging into poop, it seems to be prudent to be conservative in how much I bite off at a time!!

Trailing Porcupine at Dunby rd

Porcupine trail heading towards the camera. Note the urine along the midline, and the trail leading right to the base of the Hemlock tree and then turning away.

The Earth Tracks tracking apprenticeship had been trailing a few different species when I ended up a little ahead of the group. I was following a clear Coyote (Canis latrans) trail when I came to another trail in the snow. This new trail appeared to come from a hill to my right, crossing over the Coyote trail and then meandered through a small low spring fed clearing where while mostly covered in snow, some spots were open shallow puddles with Watercress (Nasturtium officinale) growing. On the other side of this patchy wet area, there was another hill thick with wide trunked Eastern White Cedar (Thuja occidentalis) and Eastern Hemlock (Tsuga canadensis) where the trail led upwards. I knew who this new trail belonged to pretty much right away due to the oscillating midline that ran through the length of the furrowed trough in the snow. Other clues were the trail width, which averaged out to about 15 cm (5⅞ in), and the occasional spotting of urine that was sprinkled intermittently along the run. This was the trail of the North American Porcupine (Erethizon dorsatum), a common fixture in the forests of Dunby rd.

I had been thinking a lot about Porcupines over the previous few days. We had encountered some chews on a Tamarack (Larix laricina) with one of my adult programs at the Guelph Outdoor School, and had followed a trail through a lowland Cedar forest along the Eramosa River. Porcupine ecology had been front of mind and I had a few questions already before following this new trail, and of course they were renewed with each new finding. When folks from the apprenticeship decided that we should follow and focus on the trail more fully, I was all in.

I took some measurements of the strides of the Porcupine, and they came in with an average of 21 cm (8¼ in), which was pretty much average based on some of the books and what I have seen so far tracking Porcupines. Most of what I could make out on the trail appeared to be a direct register walk, with the hind feet landing in the spot where the fronts had just been moments before, though I did find a lot of the trail to be nondescript due to the fluffy loose snow. The trail seemed to both meander and appear like the Porcupine was going someplace specific. If I were to interpret the trail in my limited understanding, it would be that the Porky knew the forest, but was also looking for something along the way; A new tree? A conspecific friend, family member or mate? According to Donna Naughton’s tome Natural History of Canadian Mammals (2012), the Porcupines breeding season is between September to November, with a possible second heat, if the first was unsuccessful, stretching the season to December, possibly even January. With this broad period of time to be mating, it could’ve been that the indivdual we were following was looking for a mate, but they may well have also been just looking for something to eat.

According to Porky researcher Uldis Roze (1989), Porcupines tend to choose a preferred tree species and stick with it. Maybe it’s a Hemlock, or a Cedar. Maybe Sugar Maple (Acer saccharum), Trembling Aspen (Populus tremuloides), or American Beech (Fagus grandifolia). It appeared to Roze when observing the trails of a few different individuals that they appeared to have preferences, and these preferences were distinct among the individuals. For example, one Pricklepig (another common name) only tasted and fed on 17 Beech trees along their trail though the trail also encountered 37 Sugar Maples, 27 Hop Hornbeam (Ostrya virginiana), and 6 White Ash (Fraxinus americana). Another individual’s trail recorded a year later counted 7 Sugar Maples singularly fed on in a line that also included Red Maple (Acer rubrum), Striped Maple (Acer pensylvanicum), Mountain Maple (Acer spicatum), Hop Hornbeam, Beech and White Ash. These two individuals appeared to demonstrate individual taste and preference for specific species in their given habitat. Perhaps the Porc-épic (french common name) I was trailing was looking for their favorite flavour in the forest? The trunk in the photo above is of a Hemlock tree, but I wish I had noted every tree they had stopped to investigate.

I continued along following the trail and with most of the rest of the crew ahead I figured I could take it slow and inspect whatever I came across. Lucky for me, I came across a small narrow woody object in the middle of the Gaag (Ojibwe name, pronounced “ga’awg”) trail. When I bent to look, I realized it was scat!

The scat appeared different than I had seen in person before, but similar to some images I have found online and on some study calls. To my eyes it looked like three pellets stuck together with a mucousy coating. When I looked close at the content it looked like disorganized masses of pale brown wood chips. I didn’t take any notes but I remember the scat being about a 1 cm (⅜ in) in diameter. I don’t remember the length of the whole string, but from my photos I would guess at 7.5 – 8 cm (3 – 3⅛ in). I didn’t smell the scat, but I wonder now at if it would have helped me to identify the contents better?

I carried the scat with me as I walked along in hopes to show the rest of the group. I left the trail I was on, noting first where it went, and then sped up then to meet up with the group. Turns out everyone was just ahead of me staring up into a Hemlock tree where a Porcupine was resting in the upper branches. I didn’t really pay attention to this Porcupine much because the group mentioned that the trail I was just following led to another tree, a very large Maple a little ways down the hill. I had noticed this tree as the trail I was on previously was leading toward the Maple rather than the Hemlock where the group was standing. I handed off the scat and made my way towards the Maple.

The Maple was pretty large. Very tall with a fairly wide trunk. There were a couple of Tinder Polypores (Fomes fomentarius) growing above a large hole in the trunk, with a lot of human tracks around the base. In the snow just in front of the hole there was a pile of Porcupine scat which appeared stepped on by boots and compressed into the snow a little. I took some photos of the scat in the tree cavity and then turned on the front facing camera, reached my phone in and pointed it upwards. The first shot was dark and blurry, but once I turned on the flash I was not disappointed.

Looking at my phone I could see that there was a Porcupine hiding out, tucked up inside the bole of this huge Maple. I have seen this behaviour a few times, but I always find it pretty endearing. Especially when I looked close and saw part of the heel of the Porky’s right hind showing like the bottom of my slippers at home. It was a cozy nook for this gentle rodent to pass their time. I have since read that the Winter den sites are usually pretty close to their preferred feeding trees, so finding this other individual so close to the big Hemlock with the first Porcupine made sense. Perhaps they share this den? I have read that North American Porcupines are pretty solitary, but have also witnessed many denned up in the same den a few times. I quickly got up and away from the Maple immediately and made my way back to see the other Porcupine in the Hemlock tree.

Over the past 10 years of noticing and watching Gaagwag (Ojibwe again, but pluralized this time) I have seen many instances of them hanging out in and feeding on Eastern Hemlock trees. I can relate with my own appreciation for the Hemlock trees. I love their beauty, their ecology and their taste, both straight from the tree, or especially, in tea. I find the flavour to be piney with a whisp of fruit, sort of citrusy, and warming, and I am incredibly grateful to the Porcupine for their help in retrieving the needles for my teas. I’m just piggybacking on some of the baseline behaviours of the Porky. Since the bark of the Hemlock is high in tannins, the Porcupine feeds almost entirely on the needles and twig tips which contain fewer tannins. They nip the terminal branches and pull them in, eat the leaves and drop the branch. If any leaves remain on the dropped twigs which have fallen to the ground, they are often consumed by White-tailed Deer (Odocoileus virginiana) or by weird naturalists who like to make Hemlock tea.

I had a question about the quality of the forage. Do Hemlock branches really have that much nourishment? I recognize that Hemlock needles contain high vitamin C, but that isn’t enough to survive on, especially throughout the coldest hardest season of the year. What do the Porkies get from the Hemlock? In the book “Porcupines: The Animal Answer Guide” by Uldis Roze (2012), he writes that “Winter foods available to the North American porcupine contain less protein, more fiber, and more plant defense compounds (toxins to deter herbivory) compared with [S]pring and [S]ummer foods. As a result, [P]orcupines lose body weight and deplete stored fat layers”. Imagine that! You’ve gotta eat as much as you possibly can throughout the Spring, Summer and Fall so that when Winter comes, you don’t die because the trash you eat doesn’t provide enough actual nourishment to sustain you (I feel like this between Christmas and New Years sometimes). What a rough go. But the Porcupines have an advantage though; their caecum. What’s a caecum, also spelled cecum, you ask? A caecum is a section of the digestive tract at the junction of the small and large intestines where food that has been eaten ferments and bacteria and fungi breaks down the cellulose and lignin from plant materials a little more. This fermentation process helps pull out more nutrition and energy from the roughage that the Porcupines are consuming. Humans, lagomorphs, some birds, and even Lungfish have cecums, though they are not found in amphibians. For different species the cecum are shaped and function differently. For humans they are relatively small and connected with the appendix.
So the caecum helps break down the weakly nutritious fodder a little bit more to turn it into something a bit better. That helps a bit through the toughest time of the year.

Another neat thing to look for on the twigs dropped by Porcupines is the conspicuous angle of the cut which remains on the proximal end of the twigs. This distinct angled cut with characteristic “steps” which can be found on twigs nipped by both rodents (the family which Porcupines belong) and lagomorphs (rabbits, hares and pikas). Some folks call this a 45° cut, but it isn’t always though it sure comes close. Just knowing this angled cut and keeping an eye out can help us start to narrow in on who cut the twig.

This brings up a question for me.. what are the mechanics of Porkies eating? What are the teeth doing exactly? I have read that when Porcupines are feeding on cambium on a tree, they anchor in with the upper incisors while swinging their jaw and scraping with the lower incisors. This is the method for chewing the cambium, but not necessarily for the nipped twigs. What do the Porkies do to get the angled steps of the nipped twigs? This is going to require a little more research on my end as I can’t seem to find anything as of yet. Perhaps I’ll go out in the Spring and try a sit spot beside some Porcupines and see what I can sort out.

Lastly, it seems like some of my other questions don’t seem to be answered in the literature, like does the astringency of a bark, namely Hemlock with their high tannic content, change the scent of the Gaag’s urine? Maybe the researchers just aren’t as interested in urine as much as I am, but that’s a whole other blog post.

It has been a lot of fun to reflect on Porcupines over the past month, considering the part they play on the land and how they play that part. They are large, lovely and seemingly more abundant than they have been in the past – perhaps as more forests grow back in Southern Ontario, replacing the farmland which replaced the forests originally, then we’ll see more and more of the North American Porcupine.

To learn more:
Mammal Tracks and Sign by Mark Elbroch and Casey McFarland. Stackpole Books, 2019.
Natural History of Canadian Mammals by Donna Naughton. Canadian Museum of Nature and University of Toronto Press, 2012.
The North American Porcupine by Uldis Roze. Smithsonian Institution Press, 1989.
Porcupines: The Animal Answer Guide by Uldis Roze. Johns Hopkins University Press, 2012.

“Do Those Prints Look “Foxy?” Tracking in Mono Cliffs Provincial Park

January 2025 Blog Post

On the weekend of January 11-12 2025, the Earthtracks Tracking Apprenticeship Group spent the weekend in the Orangeville area.  On Sunday we spent the day at Mono Cliffs Provincial Park, where we wound up and down the limestone valleys and ridges, being led by the animals who had gone before us, including primarily white tailed deer, fox and coyote.

We had a  close encounter with two deer who came upon where we were eating and were startled by our presence.  It was fascinating to try to piece together the order of events based on the prints, and try to determine the root cause of the deer’s movement in the middle of the day.

Were they driven towards us by coyotes?  Was one walking by when it picked up our scent and then became vigilant, bounding to get away from us?  Was the second deer alerted by the first?  Why did they run in opposite directions?  There were so many beds!  Somewhere between seven and nine, all within 50 m of our lunch fire.  We’ll never know exactly what happened, but reviewing the movement of the deer and coyote by examining their tracks was an excellent exercise in looking for the wisdom of the tracks.

We also had several opportunities to observe places where deer had urinated on the trail.  We enjoyed smelling the pine-scented urine, and postulated on which deposits had been made by bucks (in front of the hind legs), and does (between or just behind the hind legs).  

Does appear to squat a bit more than bucks.  Bucks seemed to “stretch out” their bodies a bit more than does while urinating. Think these pictures are both does.

While studying the deer sign was delightful (especially since it is my focal species), I was most interested in the coyote and red fox trails.  So often, as I track these two species at home, it often takes me a bit of time to settle on which species I am actually observing.

As I have been well-taught by Alexis, Byron and now Rob Baker, the tracker must be wary of using single factor reasoning when looking at prints to decide on what species is being observed.  When deciding between fox and coyote (two species commonly found in close association), there is sometimes overlap between print size, and fox and coyote use many, if not all of the same gaits.  

This blog is an attempt for me to  outline some of the distinguishing factors between these two species. 

Starting with foot morphology.  Fox and coyote are both canids and as such, both have four toes that usually register on both their front and hind feet. Both have feet that are symmetrical if bisected lengthwise. Both have front feet that are slightly larger than their hinds.  The sizes of their feet can overlap because a small coyote and a large fox may have feet that are the same size.  Both can appear to have an X in the negative space of their paws.  

Their feet do, however, have some features which differ.  The paws of the fox are much more furry than those of  the coyote. While it is hard to see this in snow, it is often quite visible in mud. Fox prints, both front and back, appear to be circular, while coyote’s front feet tend to be rounder, and their hind feet more circular.  Foxes have claws that are semi-protractable, so do not appear in prints as consistently as those of coyotes.

Note the fur on the pad of this fox

Another feature on prints of the front feet of the red fox, is a straight “bar” or “chevron” created by the backmost portion of the metacarpal pad.  The bar/chevron is absent in coyote prints. Mark Elbroch writes that ‘this is a key feature for quick identification’. 

The chevron or bar is clearly visible in this photo.

As someone who has only been tracking for three years, I rarely actually have been able to see the chevron. As with the hair, it seems easier to find in mud than in other substrates.  I sometimes see it in snow as well.  As in all of the tracking, part of the science is knowing what to look for.  

Ensuring I am not using single factor reasoning in identifying a species, my next step after looking at the prints of the animal, is to look at their gaits.  Both fox and coyote have a baseline gait of direct register trot.  Both will commonly side trot, and will move between other gaits depending on substrate and what they are up to (scouting, hunting, scent-marking and so on).  The difference between the species should be their stride and trail width; because coyote are taller and have longer legs than fox, it stands to reason their strides will be longer and their trails wider.

Looking at trail width and stride length, though I find once again that there is overlap between the species, regardless of the gait.  Measurements alone, it seems, cannot rule out one species or the other completely.

Another feature to consider is habitat.  Once again we find that both species are generalists who thrive in a wide variety of habitats.

What about social behavior?  Here is another factor to consider.  Foxes, outside of breeding season, are usually more solitary than coyotes.  Coyotes, although they may sometimes live alone, are more frequently found in packs.  At Mono Cliffs all of the coyote sign we observed appeared to be from multiple animals.  The fox, however, seemed to be alone.

A sure fire way to tell apart these canines is through their urine. Coyote urine, in my experience, really just smells like dog urine. Fox urine, on the other hand smells very much like a skunk.

So how to tell the difference between these two in the absence of urine?

Alexis likes to say that fox prints are more “dainty”.  He’ll also say, “that looks more foxy to me’.  

Until the day comes that I can look at a trail and say “that looks foxy”, I’ll have to rely on a combination of all the features above and more, to figure out who is at the end of that line of canine tracks ahead of me on the path.

Diana

All photos taken by me.

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