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January 2020 Natural Mystery

posted Jan 7, 2020, 11:55 AM by Jonathan Poppele   [ updated Jan 7, 2020, 11:56 AM ]


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December 2019 Natural Mystery Answered

posted Jan 7, 2020, 11:18 AM by Jonathan Poppele   [ updated Jan 7, 2020, 11:34 AM ]

Our December Natural Mystery was a bit of a trick question--but many of you were quick to see through the charade and correctly identified the critter that left this track. Congratulations to Chris Albert, Thom Bergstrom, Kim Cabrera, Paul Glasser, Rob Grunewald, Amy Manning, Megan, and Kirsten Welge who identified what species made this track.

This is the indirect-register of a domestic cat. The photo shows the left-side tracks--with a single toe from the front foot showing next to the full print of the hind. Let's get into how people worked this out.

Many of you began by considering, then eliminating, other candidates. Amy Manning points out that all of the local mammals that leave 5-toe tracks in this size range (such as skunk, mink, or a small raccoon) show distinct claw marks. While Thom Bergstrom succinctly states that the print "just didn’t look right for me as a mustelid."

Paul Glasser noted that "The print was in snow and I could see the fur imprint all around the track, meaning that what showed as the heel pad was all there was to the heel." Based on this, Paul eliminated species that have a longer heel that may register inconsistently, such as skunk, raccoon and marmot.

Kirsten Welge adds some more detailed notes distinguishing what we see here from weasel and skunk tracks:

"Weasel tracks show more negative space between toes and palm pad. Mustelid fronts will show more radial symmetry while mustelid hinds will show a more canid-like 'boxy' shape, with a larger gap between toe 2 and toe 1. In a skunk track, I'd expect to see claws registering in front of the toes. The toe structure doesn't match, either."

With these fived-toed animals eliminated, we need to consider other possibilities. And, as Amy points out "If you cover up the toe nearest to the ruler, this looks like a classic cat track." Kim Cabrera, Rob Grunewald and Kirsten added a few more details about what makes this a classic cat track:

"The negative space is C-shaped and the metatarsal pad is large related to toe size. Size is consistent with domestic cat. Bobcat would be larger. The leading toe shows that this is from the left side of the body."  -Kim

"The toes form a C-shape with a prominent palm pad, no claws showing, which is characteristic of a domestic cat. Left side in part because the second toe from the right side is longer than the third toe.
"  -Rob

"The track shows a large, slightly distorted M-shaped palm pad, C-shaped negative space and five small, teardrop shaped toe impressions. Toe 3 is the leading toe for felids, making this a left hind print."  -Kirsten


And, indeed, this is a domestic cat track. But cat tracks typically show four toes, not five. There were two different explanations offered for why this particular cat track might show five toes. As several people noted, domestic cats sometimes have extra toes. As Rob Grunewald shares:

"Cats can have extra toes, either polydactyl or feline radial hypoplasia. For polydactyl cats the extra toe(s) are separated from the normal ones like a dewclaw, while cats with radial hypoplasia have extra toes right next to the normal toes, which looks like this picture, one extra toe on the left side."

Kim Cabrera considers extra toes, and offers another explanation:

"One possibility is that this is a polydactyl cat, with five toes. But, I think this one is not a polydactyl cat. I think it's an overlap of prints because of the angle of that outside toe, which is from the front foot. The rest of the front track got obliterated by the hind track, which landed on top."

Kim is correct right that the arrangement of the toes isn't a fit for a polydactyl cat. But what about radial hypoplasia? I know for sure that this is an indirect register, because I was able to see the entire trail, but the photo only shows this one track. I am not familiar with the foot structure caused by hypoplasia in cats, so I don't know if we can rule that out based on morphology alone. Based on a little research, however, I think we could consider it highly unlikely. Feline radial hypoplasia describes the severe under-development of the radius (forearm bone), which can lead to the animal growing extra toes. Cats with this condition have abnormal posture, often sitting up on their hind legs like a squirrel. The condition is considered a fairly serious genetic defect, and caretakers of such cats are advised to keep them indoors and consult with a specialist veterinarian to provide the long-term management of their condition that is essential for good quality of life.


Thanks to everyone who submitted an answer, and congratulations again to Chris, Thom, Kim, Paul, Rob, Amy, Megan, and Kirsten for identifying this very unusual feline track.


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January Scavenger Hunt: Tiny Trails

posted Jan 7, 2020, 9:36 AM by Jonathan Poppele   [ updated Jan 7, 2020, 9:37 AM ]

Last month's Scavenger Hunt yielded a number of observations of tiny trails -- 2x2 bounding patterns left behind by long-tailed shrews, deer mice, and meadow voles. A number of these trails look surprisingly similar. Which brings up the question, how can we distinguish between the trails of our smallest mammals? This can be even more of a challenge when the animal modifies its gait to accommodate deep snow (well, deep for a mouse at least).

This month, I invite you to join me in search of tiny trails. Seek out and identify trails left by members of the following groups:

1) A Mouse (Peromyscus species)
2) A Vole (Microtus species)
3) A Shrew (Family Soricidae)

For an added challenge, search out and distinguish the trails of:

1) A Long-Tailed Shrew (Sorex species)
2) A Short-Tailed Shrew (Blarina species)
3) Similar Size Trails from Other, Unrelated Animals (e.g. salamander, junco, least weasel, etc.)

Since some of these trails can look nearly identical, investigate (and document!) them well enough that both you and other observers can feel confident in the identification. Look for scat or other sign along the trail. Find where the trail begins or ends. Look for changes in gait.

I look forward to seeing what you find, and learning more about how to distinguish the trails of our tiniest track-makers.

Share What You Find

Please share what you find to our iNaturalist project: Minnesota Wildlife Tracking Project: Scavenger Hunt. This is an open project, and anyone with an iNaturalist account can join and add observations.

You can set up an iNaturalist account here.
And join the project here.

December 2019 Natural Mystery

posted Dec 3, 2019, 5:40 PM by Jonathan Poppele   [ updated Dec 3, 2019, 5:40 PM ]


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November 2019 Natural Mystery Answered

posted Dec 3, 2019, 4:50 PM by Jonathan Poppele   [ updated Dec 4, 2019, 12:25 PM ]

Everyone who sent in an answer correctly identified these as woodpecker tracks. Congratulations to Mike Watling, Kim Cabrera, Terry Hunefeld, Kirsten Welge and one anonymous contributor who all identified these tracks to the species. A further congratulations to Kirsten Welge, René Nauta and our anonymous contributor who worked out what direction the bird was facing—a very difficult task with these nearly symmetrical zygodactyl tracks.

These are the tracks of a Northern Flicker, which was facing toward the bottom of the frame when it left these tracks. To break this down, I'll first turn things over to our anonymous contributor for a quick primer on zygodactyl feet:

"Zygodactyl feet only occur in some species of birds. Zygodactyly refers to the fact that the 1st ("thumb") and 4th toes are or can be reflexed rearward. In Minnesota, the species likely to display this trait are woodpeckers (including the Northern flicker), some swifts, ospreys, and owls. Roadrunners (and cuckoos), parrots (psitticines), and other birds also display this trait. There's another version of a reflexed toe (toe 2 pointed rearward) but it only occurs in species that reside in tropical forests. (Not that some swifts can move 1st and 4th toes either forward or rearward, which is a different type of foot structure.)"

Kirsten shared many of these points as well, while also noting that "the zygodactyl foot is the second most common toe arrangement in birds."

Our anonymous contributor continued with a few words about why this is a Flicker:

"It's not an owl because the straightest part of the track is on the outside of the foot. These feet belong to a bird probably just under crow-sized. You mentioned that this bird is seen here in both spring and fall. Northern flickers are common in MN year round, and a flicker seems to be the closest fit for size and pattern."

Mike echoed this, stating simply that “the size fits well with a Northern Flicker.” Terry noted that “Pileated woodpecker and other zygodactyls have much more robust toes and/or wider 'Ks' than Northern Flickers." Kim added some behavioral clues, pointing out that “Flickers usually hop when on the ground, so their tracks are usually paired like this. They are often seen on the ground, so this is a fairly common bird track to find.” Kirsten similarly reasoned that, in addition to the difference in size, "Downy, Hairy, Red-Bellied, and Pileated Woodpeckers regularly feed along trunks and branches, not on the ground like Flickers"

As for what direction the bird was facing, our anonymous contributor offered this very simple and accurate analysis:

"This bird seems to be facing downward, since the discrepancy in toe length is greater between 1 & 4 than 2 & 3, and the largest length discrepancy is in the two toes in each track oriented toward the top of the image."

Kirsten arrived at the same conclusion after taking a deep dive into woodpecker foot morphology. In her research, she found the terrific photo shown here (as well as this one and this one), and came up with these notes about woodpecker feet:

1) The hallux (Toe 1) is consistently the shortest toe. It’s also the most delicate looking of the toes.
2) Toe 4 consistently looks like the longest toe. Interesting, it also looks like the most robust of the toes.
3) The difference in length between hallux and toe 4 is greater than the difference between toes 2 & 3.
4) It also looks like the splay between toes 1 & 4 may be greater than that between toes 2 & 3.
Based on this, the hallux & toe 4 are pointing to the top of the photo: this bird is heading towards the bottom of the picture."

This is exactly correct. Toe 4 looks the longest and Toes 2 & 3 are closer in length than Toes 1 & 4. Several people noted in their answers that Toe 3 is the longest in Flickers. Which is true. Sort of. In woodpeckers, Toes 2 & 3 are partially fused at their bases, so only part of the shaft of Toe 3 is visible beyond where it joins Toe 2. This makes Toe 3 appear slightly shorter in the track than Toe 4. Check out the photos Kirsten turned up and this month's Featured Track Illustration for a close look at flicker track morphology.

Thanks again to everyone who submitted answers to this month's Natural Mystery, and congratulations again to Kirsten, Mike, Kim, Terry, René and our anonymous contributor.


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Scavenger Hunt: Two-by-Two

posted Dec 2, 2019, 1:03 PM by Jonathan Poppele   [ updated Dec 3, 2019, 4:49 PM ]

Buck rub
Thanks to everyone who participated in our first Scavenger Hunt. We received signs of deer during the rut from trackers in Minnesota, Tennessee, Texas and California. On the right is an antler rub documented by Mark Erickson, a member of our Cedar Creek Wildlife Survey team. Swing over to our iNaturalist project to see what else people found.

Our December Scavenger Hunt will be for track patterns. For many of us in northern climates, this is the beginning of the snow tracking season. Often in snow, track patterns are clearer than the prints themselves—and sometimes all we have to go on for identification.

Our December Scavenger Hunt includes three track patterns which can look quite similar, but are produced by completely different gaits. Over the coming weeks, I invite you to look for examples of each of the following track patterns:
  1. 2x2 Walk (aka “raccoon walk”)
  2. 2x2 Bound (aka “weasel bound”)
  3. Side Trot (aka “canine trot”)

For an extra challenge, try to find and document any of the following. Note that some of these are exceptionally rare.
  1. A 2x2 Walk pattern left by an animal other than a raccoon
  2. A 2x2 Bound pattern left by an animal other than a weasel
  3. A Side Trot pattern left by an animal other than a canine

Share What You Find

Please share what you find to our iNaturalist project: Minnesota Wildlife Tracking Project: Scavenger Hunt. This is an open project, and anyone with an iNaturalist account can join and add observations.

You can set up an iNaturalist account here.
And join the project here.


Some notes on terminology

“Track pattern” refers to an arrangement of footprints on the ground. “Gait” refers to the way an animal moved its body to travel. Track patterns are generally named for the gaits we presume are used to create them. We infer information about the gait an animal was using by studying the track pattern – but when we are looking at the ground, we are always looking at a track pattern, never a gait.

Some authors refer to the “2x2” Bound” track pattern as a “2x2 Lope.”

November 2019 Natural Mystery

posted Nov 7, 2019, 10:34 AM by Jonathan Poppele   [ updated Nov 7, 2019, 10:35 AM ]


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October 2019 Natural Mystery Answered

posted Nov 7, 2019, 8:06 AM by Jonathan Poppele   [ updated Nov 7, 2019, 8:11 AM ]

Our October Natural Mystery was an obscure, partial track found on the banks of the Connecticut River near Northfield, Massachusetts. Guesses for who made this print ranged from birds and reptiles to marsupials and rodents. Congratulations to Kim Cabrera, who was the only person to successfully identify the animal that left this print. Kim also identified which foot make this mark. This is the left-hind track of an American Beaver.


I'll let Kim take it from here:

"The toes of this animal are wide and rounded at the ends, with a hint of a claw. My first impression was a turkey track, but I ruled that out due to the wider toe marks and blunt claw marks hinted at here. This lead me to think it was a beaver track.

The track has been heavily rained on and is very aged by this weathering. A beaver's tail drag will often obliterate most of the track. When this happens, the outer toes are sometimes all that are seen from the hind tracks. I think that might be the case here. The beaver's tail drag made most of this track disappear before it got rained on. The rain took care of the rest of the micro details. All we are left with for evidence here is the vague toe tracks and some vague impressions from the metatarsals. The marks in the photo that are most prominent are the outer two toes, toes 4 and 5, making this a left-hind foot."


I would add to this two other points. First, we can see a hint of the right-hind foot in the upper right-hand corner of the photo, which helps us confirm that this is the left-side track we are looking at. Second, beavers walk with their weight set well to the outside of their hind feet. The outside toes usually register more deeply and clearly than the inside toes, whether or not the tail further obscures the track. It is fairly common to see only toes 3, 4 & 5 showing in a beaver hind track—even clear, fresh tracks in good substrate.

Kim goes on to make one final note about beaver tracks:

"Beavers also leave some odd-looking tracks when they are swimming in ponds. These tracks in bottom sediments show up when the pond water evaporates. I don't think this is one of those tracks because the toes are relatively clear and don't appear to have been made by a swimming animal."


We saw some of these tracks near by where this photo was taken. Just as Kim suggests, the details in the prints were less crisp. In addition, the track pattern was narrower with a longer “stride,” as if the animal was trotting. You can see an image of that print (though unfortunately not the trott-like track pattern) here on iNaturalist.


Congratulations again to Kim Cabrera for her successful IDs of this very obscure track!


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Scavenger Hunt: In A Rut

posted Oct 30, 2019, 1:07 PM by Jonathan Poppele   [ updated Nov 19, 2019, 11:52 AM ]

Welcome to the Minnesota Wildlife Tracking Project's newest challenge, the Scavenger Hunt. The purpose of the Scavenger Hunt is to get us out in the field searching for specific tracks & sign. It's one thing to identify a track or sign we encounter, but we need a deeper understanding of animal behavior to know where to look for them in the first place. The Scavenger Hunt is designed to help us build this deeper understanding, deepen our connection with our local landscapes, and give us an opportunity to share the journey.

Each month, I will post a short list of tracks and sign to seek out and document on our club's iNaturalist project. In keeping with the season, this month's scavenger hunt focuses on deer sign during the rut.

For the coming month, I invite you to seek out and document as many of the following as you can:
  1. Deer Scat
  2. Buck Rub
  3. Deer Scrape

For an additional challenge, look for fresh sign:
  1. a deer scat that is still damp with mucous
  2. a buck rub with curls of bark that have not dried out
  3. a deer scrape with a patch of soil still damp with urine

For each sign, take a photo and post it to the Minnesota Wildlife Tracking Project: Scavenger Hunt iNaturalist project. I will share a selection of the photos when I post next month's Scavenger Hunt.




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October 2019 Natural Mystery

posted Oct 15, 2019, 7:59 PM by Jonathan Poppele   [ updated Oct 15, 2019, 8:00 PM ]


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