September 2019 Natural Mystery

posted Sep 12, 2019, 1:49 PM by Jonathan Poppele   [ updated Sep 12, 2019, 1:50 PM ]

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August 2019 Natural Mystery Answered

posted Sep 6, 2019, 11:29 AM by Jonathan Poppele   [ updated Sep 6, 2019, 11:31 AM ]

Our August Natural Mystery was a scene from our 2018 Cloquet Wildlife Survey. On August 17, we held our 2019 survey at the Cloquet Forestry Center. You can read about that survey and what our teams found here. We didn't see any sign from this species in our 2019 survey, but a number of you had no trouble identifying the culprit in this photo. Congratulations to Paul Glasser, Kim Cabrera, Katherine Greene, Brendan White & Kirsten Welge who all sent in correct answers.

This is the scat and tracks of a bobcat. Beginning with the scat, Kim notes that it has:

"a segmented appearance and appears to be densely packed with fur, which is twisted up inside. The outer coating is smooth. There is grayish material inside too. All characteristic of felid scats. A scrape is not obvious, but bobcats do not always make scrapes."

Katherine, Brendan & Kirsten echoed many of these points, while also noting the blunt ends on the scat. Kirsten goes on to measure the scat at "roughly 7", with a max diameter of 1" [placing] it on the larger side for bobcat."

Nearly everyone also commented on the tracks. Katherine went into the most detail, offering these observations:

"The print at top right above the ruler shows 4 toes, and a large heel pad relative to the toes. The toes are not symmetrical to the heel pad. The negative space between the toes and the heel pad is "C" shaped and narrow. The length of roughly 2" is within range. The overall shape of the track is round/wide, not elongated/oval."

Finally, Katherine reminds us that the Cloquet Forestry Center is within the known range for bobcats. Bobcats range widely across most of the United States, but are absent from a band that extends from Upstate New York to the Eastern Dakotas. They were exterminated in most of the Ohio Valley, upper Missisipi Valley, and southern Great Lakes region in the early 1900s(1), but in recent decades have been reestablishing themselves in much of this historical range as shown both by the IUCN Red List's range map, and observations on iNaturalist. They are still absent from Southwestern Minnesota and rare near the metro area, but they are common and well established near the western tip of Lake Superior.

Thanks again to Paul, Kim Katherine, Brendan & Kirsten for sharing your answers and insights.

  1. Peterson, R.L., & Downing, S. C. (1952). Notes on the bobcats (Lynx rufus) of eastern North America with the description of a new race. Contributions of the Royal Ontario Museum of Zoology and Palaeontology, 33:1-23. Cited in Lariviere, S., & Walton, L. R. (1997). Lynx rufus. Mammalian Species, (563), 1.

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Cloquet Wildlife Survey, August 2019

posted Aug 29, 2019, 10:41 AM by Jonathan Poppele   [ updated Aug 29, 2019, 10:41 AM ]

On August 17, a group of four trackers and naturalists from the Minnesota Wildlife Tracking Project join students from the University of Minnesota's Natural Resources programs for our second summer Cloquet Wildlife Survey. They survey took place at the Cloquet Forestry Center during it's Summer Field Program for undergraduates.

The Summer Field Program focuses on forestry, but includes a smattering of field experiences in wildlife biology as well. One of these is the opportunity to observe a black bear immobilization. Each day of the program, staff set a culvert trap for a black bear. The morning we arrived, the trap caught a bear, so we put our tracking survey on hold to join the students for the immobilization.

Our introduction to bear immobilization began with a primer on darting and drugging the animal. The field staff went through the preparation of the ketamine that would be used to tranquilize the bear, and the dart that would deliver it. Ketamine is a widely used anesthetic in veterinary surgery and is considered safe and effective for immobilizing animals for research. The process of preparing the dart was more complicated that any of us observers had expected, involving well over a dozen steps and taking about 20 minutes to demonstrate. When the dart was ready, we were led to the culvert trap and watched from a distance as the researchers darted the bear.

Once the bear was under, students were invited to assist with moving it out of the trap and working through a basic regimen of measurements. The bear was a young male, likely two years old based on tooth wear. He weighed 175 pounds and had very low body fat – typical for this time of year.

Badger den
While the bear was out, we trackers had the opportunity to examine his feet up close. A couple things we noticed: First, his front feet were considerably wider than his hind feet. The discrepancy seemed larger than some of us would have guessed based on tracks I have seen and left us wondering if there is a degree of sexual dimorphism in this trait. Do males have more disproportionately larger front feet compared to females? We also noted how high the claws sat on the toes. As Sue Mansfield has pointed out to us, though bears have very long claws, they often do not contact the ground when the bear is walking.

When the bear began to twitch his nose and move his tong, the researchers stopped taking measurements and retreated a bit to allow the bear to recover. Our tracking group took the opportunity to slip off to our survey routes.

A group of 13 students joined our foursome for the tracking survey. We split into two teams and shuttled to the southern and eastern edges of the property. From there, each team followed one of the forest roads back to a central rendezvous just south of the main campus. The roads of the Forestry Center offer a mix of surfaces: hard-packed double track, gravely, grass-overgrown, and sections of perfect sand. There were enough of these natural “track traps” along the routes to find a number of interesting tracks and trails.

Both of the teams found coyote scat and fresh coyote tracks along the survey routes. At the same time, neither team saw any wolf tracks and the only wolf scat we spotted was at least a few months old. This stood in sharp contrast with the previous year's survey when our teams found several fresh wolf scat along each mile of these roads and no sign of coyote activity. What has had the wolves move away from this immediate area and the coyotes move in?

Despite the absence of fresh wolf sign, the deer activity suggested that they were still near by. Deer sign was scarce farthest away from the campus and the areas of greatest human disturbance. As we approached the more human impacted areas, deer sign became more dense. The pattern is common in semi-wilderness areas with a stable wolf population—deer seem to focus their activity in a ring around the areas of greatest human impact just a little closer in than the wolves are comfortable. Yet despite this apparent pattern in the deer's behavior, there was no sign that the wolves had been hunting here for many months.

There were other active predators in the area, however. The team walking in from the east found a series of large excavations along the roadside that included one fresh hole with tracks in the fresh dirt. The palm pad in the track had the characteristic C-shape of a mustelid, revealing the excavator to be an American Badger.

Porcupine track
The team walking in from the south found a smaller set of mustelid tracks, these belonging to a long-tailed weasel. The team found two different weasel trails, one with enough detail to identify the prints and the other that they identified from its gait in loose sand. We know from past surveys that fisher also live in these woods, but these mustelids spend little time on roads and their tracks eluded us this time out. But the same was not the case for one of their best known prey, the porcupine. The team coming in from the east found porcupine scat long the road, which they identified based on size and content. Meanwhile, the team coming up from the south found a long stretch of porcupine tracks along a section of sandy double track.

Other highlights from the day included finding the tracks, then probing sign, and finally scat of Northern Flickers; tracks of jumping mice (which are apparently quite common in these woods); a lovely assortment of frogs, toads, butterflies and spiders; and the delight of being in the field with a group of young nature geeks who were quizzing each other on the Latin names of trees.

It was a lovely day in the field and we look forward to returning to Cloquet next fall to join up with the students of the Summer Field Program once again to explore the north woods forest.

August 4 Bird Language Sit

posted Aug 12, 2019, 10:30 AM by Jonathan Poppele   [ updated Aug 12, 2019, 10:33 AM ]

On August 4, we had a delightful Bird Language sit at the Minnesota Valley Wildlife Refuge. The sun was out and the temperature was comfortable. As we settled in we may have triggered a couple of alarms from house wrens. Early in the sit a couple northern cardinals made their way through the area from east to west with some song and contact calls. During the second period, there was a cascade of sounds and alarms that started in the west and traveled northeast across the sit area. A red-tailed hawk was chasing a blackbird from the west during the third period which evoked some mild agitation in the woods by a couple birds. During the final period the northern part of the sit area got quiet and tense, something we observed in other sits during the summer. We have hypothesized that there could be fledging sharp-shinned hawks in the area that are putting songbirds on edge. However, on this sit we didn't see one.

August 2019 Natural Mystery

posted Aug 12, 2019, 10:01 AM by Jonathan Poppele   [ updated Aug 12, 2019, 10:04 AM ]

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July 2019 Natural Mystery Answered

posted Aug 10, 2019, 4:10 PM by Jonathan Poppele   [ updated Aug 10, 2019, 4:23 PM ]

Our July Natural Mystery came from Cedar Creek Ecosystem Science Reserve, where we held our Summer Survey on July 13. You can read about the summer survey and what our teams found (which included more members of this species) here. Congratulations go out to regular contributors Jim Carretta, Kim Cabrera and Kirsten Welge who each identified both the species and which foot left this track.

As Jim Carretta succinctly notes, this track comes from a Sandhill crane, left foot.

Kim Cabrera adds a little more detail, noting that the only other track that is really close in appearance is that of a wild turkey. She then explains:

"Turkeys have tracks that approach this size, but their toes are shorter, particularly toes 2 and 4. The inner toe is shorter on both species, making this a left foot. The toes of the sandhill crane are more straight, without the sort of bulbous appearance of turkey toes. They look straight and slim compared to turkeys. The turkey's toes are sort of bumpy due to the musculature."

Kirsten Welge also notes the straighter toes of this track compared with turkey and adds a few additional details:

"What I see:
  • Game bird track form
  • Webbing visible between upper two toes (toes 3&4)
  • Length of 4.25”
  • Matches game bird morphology and size range (3 ¾”-5”). However:
  • Turkey tracks tend to show bulbous, segmented toes. This track has smooth toes.
  • Elbroch notes that turkeys have webbing between toes 2&3 and 3&4. This track only shows webbing between toes 3&4.
Sandhill Crane:
  • Matches game bird morphology and size range (3 ¾” -4 ¾”).
  • Tracks show smoother edges to the toes than turkey tracks.
  • Cranes only have webbing between toes 3&4 – which makes this a match for this track.

These are all good tips for distinguishing turkey from sandhill crane tracks. I'll add a just a little more to what these trackers shared.

First, several people wrote in their answers that the track does not show a hallux, but this is not correct. The claw of the hallux is visible in the photograph as a dot about ¾” behind and just to the outside of the metatarsal pad. Look very, very closely at the full resolution photo and you may see a hint of the tip of the toe registering as well. The narrow impression of the claw on toe 1, together with the narrow claw marks on each of the other toes, offers another clue that this is a crane track and not a turkey track. Turkey nails are broad and blunt, like "Lee Press On Nail," and are designed for scratching. The base of the nails are nearly as wide as the tips of the toes. Sandhill crane nails are much narrower. When the nails register clearly, there is a distinct narrowing between the tip of the toe to the shaft of the nail.

Finally, sandhill crane tend to spay their toes much wider than turkeys. Turkey tracks typically show a splay of a little over 90° between toes 2 & 4. Sandhill crane tracks sometimes splay nearly 180°, and almost always splay wider than turkey. In soft substrate such as loose sand, where we often find both turkey and sandhill crane tracks at Cedar Creek, I find the splay of the track to be one of the most useful traits for distinguishing these two species.

Thanks again to Jim, Kim & Kirsten for sharing your answers and insights. And thanks to everyone who wrote in and took a stab at this mystery.

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Cedar Creek Wildlife Survey, Summer 2019

posted Aug 10, 2019, 4:09 PM by Jonathan Poppele   [ updated Aug 12, 2019, 10:14 AM ]

On July 13, our team of 15 trackers and naturalists spread out along the roads of Cedar Creek Ecosystem Science Reserve for our fourth Summer Survey. We have come a long way since our first survey on August 7, 2016. In the past three years, over 100 people have participated in one or more of the thirteen surveys we have done at Cedar Creek. Our core group has grown and developed--both in numbers and in skill. Some of our earliest volunteers, such as Kari Skoog and Mark Erikson, have taken part in nearly every survey and are now helping to lead our teams in the field.

For our Summer survey, our group divided into three teams and explored the North Unit, the area around Lindeman Lab, and Old East Bethel Blvd along the western edge of the bison enclosure. The largest surprise of the survey was the modest diversity of mammal tracks our teams found. Unlike some past surveys where we have recorded the presence of as many as thirty species of mammals, our teams verified the activity of just nine this time around: coyote, red fox, raccoon, white-tailed deer, eastern grey squirrel, eastern chipmunk, plains pocket gopher, mole, and shrew. We saw no signs of bears, skunks, weasels, cats, other squirrels, large rodents, rabbits or mice. Significantly, for the second survey in a row, we also did not see any signs of wolves.

It's good to remember that while our surveys can verify the presence of a particular species on the landscape, it is more challenging to interpret what the absence of sign means. We can only record what we find, and what we find depends not only on where we choose to explore, but also the weather, seasonal variation in animal behavior, and the substrates available to us. Our teams regularly find fisher tracks in our winter surveys, but have yet to verify any during the summer. But it seems unlikely that the fisher leave the reserve in the summer months--they just don't use the roads much. There are about as many bears, skunks, weasels, cats and so forth on the property now as in previous seasons. We just didn't happen to see their tracks or sign this time out. But in the case of the wolves, we may be able to read a bit more into our observations. Wolves make heavy use of the roads, and frequently mark road/trail junctions. They also affect the behavior of other animals in dramatic ways. Up until this spring, our teams had found wolf tracks or scat on every single one of our surveys. We have now had two surveys in a row where we haven't seen any. Together with this, the behavior of the coyotes seems to be shifting in the North Unit in a way that suggests there are no wolves in the area. At least for now, it appears that the wolves have left Cedar Creek.

Arabesque Orbweaver
Our team in the North Unit followed the main road in from Gate 7 and up past Field A. From right inside the gate, the team found the tracks deer, red fox, and coyote using the road. The deer and red fox were a familiar sight, but the coyote have been scarce along this roadway in the past. Only recently have we seen coyote tracks along the road. And in each of our past three surveys, they have become more numerous, moved more comfortably in the open, and extended farther from the edge of the property into the area where we had seen the most wolf sign in the past. Interestingly, though the coyotes were clearly making their presence much more known, the red fox did not appear to be shying away from the open--at least not yet. The boldness of the coyotes along the teams entire survey route strongly suggests that the wolves have moved on.

Besides the deer, fox, coyote, and ubiquitous pocket gopher mounds, the only other mammal sign the team found was a lovely set of grey squirrel tracks in mud, just past the edge of the woods. But there was plenty of other diversity in the North Unit to pique our naturalists's interest including toad tracks, a tiny wood frog, a beautiful Arabesque Orbweaver, and Summer Azure butterflies feeding on an old coyote scat.

In the area around Lindeman Labs, fox and deer were the order of the day. On the trail between Lindeman Lab and Cedar Bog Lake, our team found the tracks, scat, digs, and scratches of several red fox. The tracks included a range of sizes, suggesting a mom and kit hunting along the road together. South of Lindeman, the team found more fox tracks along with larger canine tracks which were likely coyote, but not clear enough do distinguish from domestic dog with certainty. Dogs are not permitted in the reserve, but our tracking surveys and the Eyes on the Wild trail camera network have both shown that they do come onto the property.

Our third team spent their time on Old East Bethel Blvd, along the western edge of the bison enclosure, with a focus on following coyote trails and exploring how the enclosure might affect their movement. The team followed the trail of a large coyote north along the road, and spotted the tracks of others in the bison wallows just inside the enclosure. The trails they spotted in the wallows mostly paralleled the road. They also found some coyote trails crossing East Bethel at points where it was easy to pass under the fence. It is clear that the coyote are very comfortable and established in this part of the reserve--and seem perfectly home among the bison.

In addition to the coyote trails, the team also found the trail of a bullsnake, some chipmunk, squirrel and raccoon tracks, and a variety of bird tracks including mourning dove, American robin, ring-necked pheasant, and turkey and sandhill crane, which our trackers are now distinguishing with confidence.

As always, our survey left us with more questions than answers. Primary among these, of course, is where are the wolves? The last time we saw evidence of them was during our winter survey when one team trailed a wolf for a couple of miles, found a kill site, and verified the presence of two different individuals. Where are they now?

Also, while it is not unusual to have a survey where we don't see any sigh of bear or skunk or weasel or cat, it is unusual to not see any of these carnivores. Was this just by chance? Or are there patterns to these animals movements that had them away from the roads we traveled at this time of year?

Many of our trackers are becoming increasingly interested in and aware of bird tracks. But there is little information available about how to distinguish the tracks of most of the birds we find at Cedar Creek. How can we build our knowledge of these small bird tracks? And given that birds, unlike many mammals, can often be seen and heard, is there scientific value in our learning to identify small bird tracks with confidence? There is no question that it is fun and enriching!

We will have a chance to explore these and other questions at our special two-day fall survey on September 21-22. I hope you can join us for one or both days. Full details coming soon.

July 2019 Natural Mystery

posted Jul 6, 2019, 11:45 AM by Jonathan Poppele   [ updated Jul 6, 2019, 11:46 AM ]

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June 2019 Natural Mystery Answered

posted Jul 5, 2019, 2:07 PM by Jonathan Poppele   [ updated Jul 6, 2019, 11:50 AM ]

Our June Natural Mystery was really a three-part question—identify the plant, identify the bulge at the end of it, and explain how it ended up on the ground looking the way it did. It is clear that we have some experienced foresters in the group, in addition to a great many excellent trackers. Congratulations to Rachael Olesiak identified every organism involved here to the species. Honorable mentions go to Deb Sweeney, who correctly identified the plant and the cause of the bulge on the twig, and to Jim Carretta who identified the animal involved and it's behavior.

Let's begin with Rachael Olesiak's succinct answer to the question:

A red squirrel chewed on the gall of a jack pine from pine-pine gall rust.

Deb Sweeney offers some additional details about the plant and the gall:

Step one is identifying the twig. It's a pine because it has needles in bundles of two. Jack pine because the needles are under 1" and are widely spread. Then let's look at the blob. It looks weird and it is on a plant, therefore it is a gall (my personal rule of thumb). Galls are specific to plants. Googling "jack pine gall" we get Pine-Pine Gall Rust which has an oblong shape and has a similar appearance.

Rachael and Deb are exactly correct. This is a Jack Pine twig with a gall on the tip caused by the oddly named Pine-Pine Gall Rust. Pine-Pine Gall Rust, also known as Western Gall Rust, is a disease caused by the fungus Endocronartium harknessii which grows in the vascular cambium of it's host. The fungus uses pine trees as hosts for both parts of its life cycle. Hence the “Pine-Pine.” A related disease, Pine-Oak Gall Rust, is caused by a fungus that requires pine trees for one part of its life cycle and oaks for another.

Jim Carretta recognized the bulb as some kind of gall, and correctly added:

The branch was one among many clipped by a squirrel while high in the tree. The photo shows some teeth marks on the gall / bulb.

Thanks again to everyone who submitted answers, and to Kirsten Welge for providing this mystery for us. I learned a lot researching this and reading the responses and hope you all did as well.

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June 2019 Natural Mystery

posted Jun 11, 2019, 8:18 PM by Jonathan Poppele   [ updated Jun 11, 2019, 8:18 PM ]

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