Date: June 6, 2026 (10:45 am – 5 pm).
Place: The location is near the mouth of the Sauble River, where it enters Lake Huron, near Sauble Beach/Sauble Falls, Ontario. It is just northwest of the Sauble River Marina and Lodge Resort and within the Chief’s Point 28 First Nation reserve. I include a map below and a typical view. A sandy road led down to the beach and then skirted along its edge. In several places, small wooded promontories projected out into the water, covered mainly with cedar. Along the edges of these points were scattered feathers, fish remains, and bird remains, suggesting repeated use by predators or scavengers. Within the forested areas, there were also fish remains, including fish heads, as well as clear otter scent-marking areas where the otters rolled and defecated.
Weather conditions: If I recall correctly, it was at least 17°C, but because of the strong wind, I felt cold. The clouds changed rapidly, alternately clearing and covering the sky, while mist raced across the land.
References:
– [1] ‘Mammal Tracks & Sign: A Guide to North American Species’, Mark Elbroch, Stackpole Books (2nd Ed.), 2019
– [2] ‘Bird Tracks & Sign’, Mark Elbroch and Eleanor Marks, Stackpole Books (1st Ed.), 2001
– [3] ‘Tracks & Sign of Insects and other Invertebrates: A Guide to North American Species’, Charley Eiseman and Noah Charney, Stackpole Books (1st Ed.), 2010
– [4] ‘The Feather Atlas’, an online resource at https://www.fws.gov/lab/featheratlas/identify.html
Observations:
Most of my observations were made around the edge of the wooded promontory. Before we reached that spot, however, we found what looked like turtle eggs that had been dug up near the sandy road by the beach. The broken oval eggs we found in the dug-up nest along the sandy Lake Huron shore at Sauble Beach were most likely from a Northern Map Turtle. This seems more likely than Snapping Turtle because Snapping Turtle eggs are typically round, whereas Northern Map Turtle eggs are oval and about 3.2 cm long. The setting also fits well: Northern Map Turtles inhabit lakeshores and rivers in Ontario, nest from June through July, and use open nesting areas near water, often in sand or gravel. Their clutches are commonly in the range of about 10–17 eggs, although larger or smaller clutches can occur. They get their name from the fine yellow, tan, or orange lines on the shell that look a bit like contour lines on a map. In Ontario, they are often seen basking on rocks or fallen logs, but they are very wary and quickly drop into the water when disturbed. See https://www.ontario.ca/page/northern-map-turtle. Here is a photo of this turtle:
Alexis Burnett from Earth Tracks thought it more likely that these eggs were from last year, as they did not look fresh. What was especially interesting was that several of the broken eggs still contained dead baby turtles. This left me wondering why they had not been eaten by a predator. Did the eggs perhaps fail for some other reason, with the nest being dug up or scavenged later?
On the same section of beach, we found fresh raven tracks. Apart from differences in size, the cut-off point between crow and raven tracks is about 3 3/4 inches. These tracks were about 4 inches long. We also discussed some of the morphological differences between the tracks of these two species. For example, raven tracks are “blockier” than crow tracks; that is, the digital pads are more prominent. We also noticed that the straddle was too large for a crow, and that the toe impressions tapered to points more steeply than they typically do in crow tracks.
Members of our group also found some bird tracks under water, which they thought were from an American Robin. I did not measure the track length, but the curvature of toes 2 and 4 was described as resembling a banana peel.
We also found what appeared to be a spider egg sac. It was round, flattened, and disk-like, about 1/4 inch across, with a silvery or slightly metallic sheen. This fits the description of flattened or lenticular spider egg sacs, which are often attached firmly to a substrate such as rock, bark, leaves, or other surfaces (see page 29 of [3]). Some antmimic spiders make shiny, tough, flattened, disc-shaped egg sacs that may be attached to stones. “Antmimic” simply means that these spiders resemble ants in their body shape, movement, or appearance. I realized that I have seen these egg sacks before, but didn’t know what they were.
We then made our way to the edge of the wooded promontory. The beach was littered with bird feathers and bird and fish remains. Here are some bird remains and bones. The scattered bones were light, thin-walled, and delicate, consistent with bird remains. Some appeared hollow or air-filled, with fragile splintered edges, rather than the denser, heavier bones one might expect from a mammal.
Among the remains was a large fish, roughly two feet long, that appeared most consistent with a Channel Catfish. The head was very wide, and the mouth contained dense pads of tiny, pin-like teeth rather than large obvious fangs. I could also see two whisker-like barbels around the mouth, although others may have been missing or obscured because the fish was dead and partly decomposed. The large paired fins near the head and the apparently smooth, scaleless skin also supported the identification as a catfish. See https://www.ontario.ca/page/channel-catfish.
Another interesting observation was six double wings of the Yellow-shafted Flicker. Here is a picture of one of the wings, and a tail feather.
Here are some more photos taken by Byron Murray (To Know the Land):
One thing I learned on this outing was to look carefully at the base of a suspected tail feather. In some of the feathers we examined, the shaft showed a slight dip or bend near its base. We also wondered why we were finding so many paired flicker wings. According to Alexis Burnett, this pattern is characteristic of birds that are preyed upon by either a Merlin or a Peregrine Falcon. This interpretation also seems to be supported by the paper linked below (thanks Byron Murray).
I found many other feathers, including what appeared to be a Bald Eagle tail feather and a Bald Eagle primary feather. The tail feather was about 12 inches long, which fits well with the Bald Eagle tail feather measurements shown in the U.S. Fish and Wildlife Service Feather Atlas. The third picture shows a much larger primary feather, about 18 inches long, which is also consistent with Bald Eagle primary feather lengths in the Feather Atlas (see [4]). The final picture shows a feature that was pointed out to me by members of the tracking group: when I ran my finger along the edge of the rachis, it felt slightly like a file because of its ridged texture. I later found a similar observation in a Reddit discussion: “Run your fingernails along both sides of the rachis, if it’s smooth then it’s definitely a goose. Sometimes bald eagle and goose feathers look very similar and that’s one way to tell the difference. An eagles rachis is ridged on the sides.” See
https://www.reddit.com/r/birding/comments/1nlynhs/what_bird_is_this_from/
There were many other feathers, for example those of a Mallard Duck (see [4]).
I also found what looked like a goose egg fragment (see below).
I searched online for some information about how to tell if egg remains are from hatching or predation, e.g. see the video linked below:
https://www.youtube.com/watch?v=KjIqMbVF-eQ
According to the video link, there are several features that can help distinguish a hatched egg from a predated one. A hatched egg is often fairly neatly broken around the circumference of the thicker, blunter end of the egg, where the chick has chipped its way out. I cannot tell for certain whether we are looking at the thicker end here, but the break does look somewhat even. A hatched egg would also normally lack obvious yolk, egg white, or blood inside the shell, although there appears to be a little staining in the picture. Another feature associated with hatched eggs is that parts of the shell or inner membrane may be curled or pushed inward, which also seems possible here. In contrast, predated eggs can have a more variable break pattern, depending on the predator, and may show messier damage or a single puncture hole, as can happen with corvids. In this case, the egg remains seem to show features of both hatching and predation. One possibility is that the chick had begun to hatch and the egg was then predated or scavenged later. According to
https://www.discoverwildlife.com/how-to/identify-wildlife/how-to-identify-egg-thieves,
a baby bird begins hatching by using its egg tooth, a small hard projection on the upper beak, to chip at the shell from inside. It usually works around the blunt end of the egg, gradually making a roughly circular line of breaks. As the chick pushes and turns, the shell opens outward and the egg separates, often leaving a jagged but fairly even break around the end. After the chick emerges, the empty shell dries; the inner membrane can contract and curl the chipped edge inward. A naturally hatched shell should not normally have yolk or egg white left inside.
My next find was the most exciting. I was looking for more otter scent-marking roll areas where the wooded edge met the beach. On a small bank that extended slightly into the forest, I found a bird skull. It looked as though it may have been left there when the lake water was higher, settling among the driftwood, feathers, and other bones along the edge. What struck me immediately was the long, sharp beak. Byron Murray challenged me to identify the species, and I made several incorrect guesses. I searched for pictures of bird skulls that seemed plausible, comparing the skull with species such as Great Blue Heron, Herring Gull, Raven, and Sandhill Crane. Eventually, I found a picture that looked very similar: a Common Loon. One distinctive feature was the two grooves running along the top of the skull. The skull I found, including the beak, was about 6 inches long, and lacked the lower beak.
Here is a site with some high-definition images:
https://virtual.imnh.iri.isu.edu/Osteo/View/Common_Loon/582.
My skull must be quite old, as the end of the beak no longer has the dark colour shown in photos. Notice the slight curvature at the end of the beak, and how far the nostril holes extend along the beak. I wondered about the purpose of the grooves along the top of the skull. After some extensive searches, I think I may have found the answer.
The Common Loon is a highly aquatic, migratory diving bird, breeding on freshwater lakes and wintering in coastal marine waters, where its ability to deal with salt water becomes important. The two grooves along the top of the skull are best interpreted as ‘supraorbital grooves’ or ‘fossae’, the bony depressions associated with salt-secreting glands. These glands help birds that live in salty environments remove excess salt from their bodies. I had wondered whether the loon was a “primitive” bird, but it is probably better described as a highly specialized diving bird. Unlike many birds, loons have many solid bones, making them less buoyant and better adapted for swimming underwater. This heavier skeleton, together with the long, sharp bill and salt-gland grooves, reflects the loon’s life as a powerful fish-catching diver. See the DigiMorph Common Loon page at
https://digimorph.geo.utexas.edu/specimens/Gavia_immer/,
the National Park Service page on Common Loon adaptations at
https://www.nps.gov/gaar/learn/nature/common-loon-3.htm,
and the Weber State cranium annotations at
https://www.weber.edu/NAA/CraniumAnnotations.html.
On my way back to the main beach, I found some fossils:
This got me wondering about the geology of the area. The fossils I found at Sauble Beach fit the broader geology of southern Ontario, where much of the bedrock is Paleozoic sedimentary rock formed in ancient shallow tropical seas. In the Sauble area, nearby Sauble Falls is underlain by the middle Silurian Guelph Formation, a reefal dolomite, which helps explain why marine fossils can turn up in local rock and along the shoreline. One of my finds appeared to be a gastropod, and another fossil that I first thought might be an ammonite was more likely a nautiloid. That makes better sense geologically, since Ordovician and Silurian rocks in Ontario are well known for marine fossils such as snails and squid-like nautiloids. See
https://uwaterloo.ca/earth-sciences-museum/educational-resources/fossils/paleozoic-fossils-ontario
Finally, on the way back to our cars, we followed a sandy road through the forest along the edge of the lake. As we walked, I heard the loud, raucous calls of a raven coming from somewhere in the woods. The calls sounded different from raven calls I had heard before: higher in pitch and more insistent. A member of our group told me that it was a juvenile raven, so I decided to investigate. I eventually traced the sound to the base of a tall pine tree. I was surprised that the juvenile was on a branch high in a tree rather than in a nest. The mother then came in to feed it, but quickly departed after noticing me. In the sound recording below, you can hear the juvenile calling, followed by the wingbeats of the adult bird as she leaves in a hurry. Here is the audio file:
Then, near this location, I spotted what might have been the nest where the young raven had been reared. I estimate it was about 2 1/2 feet across and some 40 feet up in the tree.
Final thoughts:
This post ended up being much longer than I intended, and I still described only a fraction of what we observed. I had a lot of fun researching the natural history behind my field observations. This is my favourite way to learn: following questions as they arise in the field, when I suddenly have a reason to know the answer.
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