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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.

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

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.

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.

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.

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.

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.

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.

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.

Shape and angle of the impression

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?