In late February this year, a Snapshot Wisconsin trail camera deployed in Vilas County captured an American marten (Martes americana). This is the first time an American marten has been captured on a Snapshot Wisconsin camera! The below American marten was identified by the trail camera host, Ashley, and the identification was then confirmed by several species experts in the Wisconsin DNR. While American marten can vary in color, they are best identified by their pale buff to orange throats, dark legs and tails, vertical black lines running above the inner corners of their eyes, and bushy tails that account for one-third of their total length.
Extirpated from Wisconsin in the 1940’s, these small members of the weasel family were later reintroduced to the state and placed on the Wisconsin Endangered Species List in 1972 due to loss of suitable habitat. Marten are restricted to the northern portion of the state where they reside in dense, mature forests with preference for areas that are a mix of coniferous and deciduous trees.
Did you know that marten are excellent climbers? They use this skill not only to hunt down prey, but also to avoid potential danger. These solitary animals are very territorial, with territories spanning an average of two square miles for males and one square mile for females. Although the breeding season lasts from July to August, fertilized eggs do not fasten to the uterine wall until January or February. Females birth two to four kits in March or April, and raise their young in tree dens without any male assistance.
There is still much to be learned about American marten, as their nocturnal lifestyle and often shy demeanor make them a difficult species to study. Follow this link for more information about American marten in Wisconsin, and stay tuned to discover what rare species will be captured next on Snapshot Wisconsin trail cameras!
Before joining Snapshot Wisconsin in 2016, I knew very little about porcupines. I grew up in Iowa where porcupines were extirpated in the 1800’s. What I knew consisted of what I learned from my grandparents as a youngster on summer fishing trips to northern Minnesota. Essentially, porcupines have sharp quills and you don’t want your dog to tangle with them. I never saw a porcupine on any of these trips but was always on alert to make sure my dog, a Miniature Schnauzer named George, never wandered too far.
My first task upon joining Snapshot Wisconsin was classifying photos from Black River Falls, where trail cameras are in place to monitor the reintroduced elk population. As I was flipping through photos, I kept seeing these critters that I couldn’t identify. They were small, rounded and dark colored, always facing away from the camera, and only appearing at night. I wasn’t sure what these could be, and we had yet to create resources to help with this task, such as the Snapshot Wisconsin Field Guide*. Sometimes I classified them as raccoons and sometimes as beaver (in my defense, our early cameras didn’t take very clear photos!) Eventually, my porcupine identification skills improved and thankfully so did the photo quality of our cameras. Porkies have since become one of my favorite species captured on our cameras. Read below to learn more about these quill-y, charismatic critters!
There is only one species of porcupine in Wisconsin, the North American porcupine (Erethizon dorsatum). Worldwide there are 23 different species of porcupines. Our porcupine is the second largest rodent in North America, only beavers are larger. Their size ranges from 7-30 pounds and 20-26 inches. They typically give birth to one young per year. Young are called porcupettes.
Porcupines are herbivores, consuming tree bark, branches, buds, evergreen needles, garden produce, and even tool handles.. A common misconception is that porcupines can shoot their quills when threatened. The quills are actually loosely attached and embed themselves in the unfortunate victim when they come in direct contact with the porcupine.
Porcupines occur in the Northern and Central Forest regions of Wisconsin. To date, we have had 4,175 reports of porcupine from trail camera hosts. These have not yet been verified and presumably include a few raccoons and beavers due to my early classification mistakes and similar errors by other staff and volunteers. A handful of porcupine classifications from southern Wisconsin (Grant, Iowa and Waukesha counties) revealed the true species to be woodchuck, raccoon, unknown bird and squirrel. Species distribution maps are quite useful for classifying our photos and Snapshot Wisconsin data will be instrumental in updating these in future.
Find out more about porcupines at the links below!
*Snapshot Wisconsin Classification Field Guide (located on the right hand side of your screen while classifying photos on Zooniverse)
May’s Volunteer of the Month is
Chris from Portage County!
May’s Volunteer of the Month goes to Chris from Portage County! Chris is a Professor of Biology at UW-Stevens Point. Chris was first introduced to citizen science around 10 years ago through the Wisconsin Bat Program. In collaboration with the Urban Ecology Center and Milwaukee area high school teachers, Chris has since developed a bat curriculum that incorporates citizen science, or as it is known in Milwaukee, community science.
Chris first discovered the Zooniverse platform about two years ago, which led him to learn about Snapshot Wisconsin. After he began hosting his own trail camera, Chris stated that he was initially annoyed by a fawn that rested in front of his camera resulting in hundreds of photos (which we are sure many volunteer have experienced!) Chris’s “aha moment” was then realizing how interesting the data collected about that fawn was – time alert, sleeping, stretching, foraging.
When asked about his advice for potential volunteers, Chris shared, “There are lots of citizen science projects, but Snapshot Wisconsin does a great job of motivating its volunteers. Start with Zooniverse. Snapshot Wisconsin was a pioneer project on this global platform and will connect you immediately to Wisconsin wildlife. If you are hooked by Snapshot like I was, you can consider hosting your own camera and become a small part of a big thing.”
Thank you, Chris! Thank you to all our trail camera hosts and Zooniverse volunteers for helping us discover our wildlife together.
Within the scientific field of animal behavior, research topics such as parental care, natural selection, and feeding tendencies seem to arise far more frequently than animal play. After all, a life in the wild tends to revolve less around play and more around survival. For some animals, however, play is an integral part of their lifestyles and ultimately their perseverance. River otters, for example, are social animals with a playful and charismatic reputation. As their name suggests, river otters do not typically stray far from waterways, and some Snapshot Wisconsin cameras are perfectly positioned to capture interesting otter behavior. We have observed otters grooming together, wrestling with one another, and – perhaps most amusingly for our staff and volunteers – sliding across the snow. At the bottom of this post there is a compilation of otter slide photos.
Undeniably, sliding across snow or mud is an effective method for locomotion when you compare it an otter’s normal gate – a cylindrical body bounding on short legs. It’s the kind of body shape that glides effortlessly through the water but doesn’t demonstrate the same sort of grace on land. Those proportions make it especially tough to traverse snow, just take it from the otter pictured on the right.
Is sliding truly just an efficient way to travel, or does the otter’s seemingly spirited nature play a role in this behavior as well? A 2005 paper published in the Northeastern Naturalist suggests that it could be both. The study analyzed 5 minutes and 49 seconds of video of wild otters in Pennsylvania. The otters were observed sliding 16 times, an excessive number for the sake of conserving energy.
The term “otter slide” doesn’t just refer to a mode of transportation, however. It can also refer to the marks near riverbanks that are left when otters slide in and out of the water. Often repeated otter sliding will occur near latrine sites, where the animals will go to deposit and read scent-coded messages from other otters in the area. The slides are such a great indicator of otter presence, that the Wisconsin DNR conducts aerial surveys in the winter to help determine population trends. Whatever the motivation is behind the sliding behavior, we certainly enjoy watching it on our trail cameras.
The Snapshot Wisconsin team is often asked why we accept data only from our Snapshot-specific cameras. While there are several reasons, the reason that was highlighted in the April 2019 newsletter was because Snapshot Wisconsin cameras are programmed to take a single photo at 10:40 a.m. each day. Although 10:40 may seem like an arbitrary time, this corresponds to the approximate time that a NASA satellite flies over Wisconsin and collects aerial imagery. (More information on how NASA data and Snapshot data are complementary can be found in this blog post.)
It may be difficult to recognize the value of a blank photo in wildlife research, but a year-long series of these photos allows us to examine something very important to wildlife: habitat condition. For each camera site, the time-lapse photos are loaded into the statistical software, “R,” where each pixel in the image is analyzed and an overall measure of greenness is summarized for the entire photo. That measure, called the Green Chromatic Coordinate, can be used to identify different “phenophases,” or significant stages in the yearly cycle of a location’s plants and animals. These stages can be delineated on a graph, called a phenoplot, where a fitted curve reveals the transition day-by-day. The 2018 phenoplot for one Snapshot Wisconsin camera site is seen below.
In 2018, 45 camera sites had a complete set of 365 time-lapse photos, but we expect many more sites to be included in the 2019 analyses. The relatively small sample size for 2018 is due in part to many counties not being opened for applications until partway through the year, but also because time-lapse data are rendered unusable if the date and time are not set properly on the camera. This may happen when the operator accidentally sets the time on the 12-hour clock instead of the 24-hour clock, or if the hardware malfunctions and resets the date and time to manufacturer settings—this is why we ask our volunteers to verify the camera’s date and time settings before leaving the site each time they perform a camera check.
The information derived from these analyses will be integrated into wildlife models. For example, the objective of one ongoing DNR research project is to understand linkages between deer body condition and habitat, which includes what’s available to deer as forest cover and food resources, as well as weather-related factors, such as winter severity or timing of spring greenup. The project currently uses weather data collected across the state to estimate snow depth, temperature, and winter severity, and creates maps based off this information.
Snapshot’s time-lapse cameras offer a wealth of seasonal information regarding type of forest cover and food sources, as well as weather-related information. In the future, phenological data obtained from Snapshot cameras could be used to create “greenup maps” that provide estimates of where and when greenup is occurring, and potentially test that information as a means of better understanding how environmental factors affect deer health, such as whether an early spring greenup improved deer body condition the next fall.
Did you know that white-tailed deer (Odocoileus virginianus) antlers are one of the fastest growing tissues known to man? For instance, human fingernails grow between 1 to 10 centimeters a year whereas white-tailed antlers grow several centimeters each day during the growing stage! Unlike human fingernails, deer antlers are composed of veins, arteries, vessels, and cartilaginous tissue. Many hunters believe that the bigger the rack the older the buck. Yet, the inspection of teeth is the only accurate indication of a deer’s age. The greatest antler size within a buck’s life is from age five to seven. Factors sure as age, genetics, and nutrition of the buck determines the magnitude of antler size. Keep reading below to learn how antlers grow and change throughout the year!
Pedicles, the area attaching the antler to the skull, are first formed on top of a buck’s head during late winter and spring and can reach up to ¼ of the ear-length. Snapshot Wisconsin asks volunteers to classify any deer with formations less than ¼ of the deer’s ear-length as antlerless, while reserving the antlered classifications for more than ¼ of the deer’s ear-length.
To create antlers in early spring, minerals in the ribs and shoulders of the buck are redistributed in his body. Velvet (pubescent skin) covers the antler and provides nutrients through the flow of blood. These nutrients cause antler growth. During the velvet stage, the antlers are very sensitive. Any impact will be painful and could, due to the fragile state, cause breakage. Nevertheless, this sensitivity allows the buck to comprehend the size of its antlers and, eventually, the buck will move through the forest with ease.
By late summer, the antlers are fully grown. Blood flow becomes constricted, causing gradual hardening and calcification. The velvet dies off in response and, like a sunburnt human, the buck becomes annoyed and wants to peel the excess skin off. The buck rubs his antlers on trees to rid himself of the velvet, exposing glabrous antlers. This rubbing strengthens the buck’s neck, which will come in handy during the rut where the buck will compete with other bucks’ antlered attacks.
Due to reduced sunlight and testosterone, white-tailed bucks’ antlers fall off around January and February. Their body absorbs the calcium between the antler and pedicle, which weakens the antler, causing it to eventually fall off. If you’re looking for a hobby this time of year, check out shed hunting! Shed hunting is the pastime of searching for antlers that have been naturally shed by antlered bearing mammals. Another great hobby for this time of year is checking out the trail camera photos captured by the Snapshot Wisconsin project! Start viewing and classify photos today!
For more information, please visit these sources:
Are you ready to celebrate Citizen Science Day?
Before we dive into the details, let’s start with what is citizen science? There are many definitions for citizen science, which may also be referred to as community science, crowd-sourced science or volunteer monitoring. The Oxford English Dictionary defines citizen science as,
“Scientific work undertaken by members of the general public, often in collaboration with or under the direction of professional scientists and scientific institutions.”
Citizen scientists partaking in Snapshot Wisconsin monitor trail cameras across to state to gather year-round data about wildlife. Data collected from the project help inform wildlife management decisions at the WDNR, and also engage the public in learning about the state’s natural resources. Snapshot Wisconsin has over one thousand volunteers hosting trail cameras across the state, and hundreds more from around the globe helping to identify the wildlife caught on camera on Zooniverse.
Citizen Science Day is hosted annually to celebrate and recognize the projects, researchers, and dedicated volunteers that contribute to citizen science all over the world. Mark your calendars for April 13th, this year’s Citizen Science Day kick-off! The Citizen Science Association and SciStarter have teamed up to promote events in celebration of citizen science. Are you interested in celebrating Citizen Science Day this year? Check out SciStarter’s project finder to find Citizen Science Day events near you!
You can celebrate citizen science any day of the year by participating in Snapshot Wisconsin, whether you are interested in hosting a trail camera or identifying the exciting critters captured on camera (which can be done from anywhere!)
If you are familiar with Snapshot Wisconsin’s crowdsourcing website hosted by Zooniverse, you likely have heard of the term #SuperSnap used by volunteers to denote especially captivating photos. Recently a slight typo, #SuperNap, not only gave Snapshot staff members a good laugh – but also a potentially catchy new phrase for hibernation? In this blog post, we will dive into the science behind slumbering wildlife in winter.
What is hibernation?
When winter rolls around, critters get creative with how to stay alive! In some cases, animals combat the considerable metabolic challenges of winter by entering into a state of temporary hypothermia, such as the black-capped chickadee. The ruby-throated hummingbird migrates south to Central America to avoid the entire winter thing all together. Others avoid the perils of induced hypothermia and the exertions of migrating by going to “sleep”, or hibernation. During this state of sleep the temperature, breathing rate and heart rate of animals drops significantly. To survive harsh winter conditions and scant food availability, animals can quite literally shut off for a few weeks at a time. If you’ve lived through a Wisconsin winter, you understand the appeal of this!
Not all sleep is created equal
There are two main sleep survival strategies that animals use in the winter. True hibernation is a voluntary state that animals enter induced by day length and hormone changes. These conditions indicate to an animal that it’s time to go into a truly deep, long sleep. Hibernation can last anywhere from several days to months depending on the species. Animals still need to wake up to drink water every one to three weeks. Waking up from hibernation every few weeks is a good idea to improve your immune system by removing those pesky parasites.
Torpor, similar to hibernation, is a sleep tactic animals use to survive the winter. Unlike hibernation, it is involuntary and induced by outside temperatures and food scarcity. Torpor can reduce an animal’s normal metabolic rate by 40 times in as short as two hours. In contrast to hibernation, torpor only lasts for a short period of time, sometimes just the night or day depending on the activity of the animal. Torpor can be considered “light hibernation”. To awake from torpor requires ample amounts of shivering and muscle contractions to return to a normal metabolic rate!
Torpor or hibernation?
Whether an animal goes into torpor or hibernation is usually based on body size. The smaller the body size, the more likely an animal is to enter into a state of hibernation over torpor. A large body requires removing higher levels of excess body heat which would make light bouts of torpor energy inefficient. Smaller bodied animals can adjust to winter conditions more quickly.
Based on what we now know about the differences between torpor and hibernation, can you take a guess as to what type of sleep the below animals use to get through the winter?
A. The black bear (Urus americanus) enters a state of TORPOR. Contrary to widespread belief, black bears go into torpor in the winter! They can turn their pee into protein through a urea recycling process and the females will wake up to give birth and go right back into a state of torpor! (source).
B. The chipmunk (Tamias spp.) uses HIBERNATION to survive the winter. A chipmunk can bring its heart rate down from 250 beats per minute (bpm) to as low as 4bpm.
C. Raccoons (Procyon lotor) enter into a state of TORPOR, along with species like skunks.
D. The common poorwill (Phalaenoptilus nuttallii), native to the western United States, is the only bird species known to truly hibernate in the winter (source). Birders may be familiar with their Wisconsin relative nightjars – the common nighthawk and eastern whip-poor-will!
Recently, I was running, lost in my thoughts, and—WHOOPS—almost tripped over a shivering opossum crossing the bike path! After we both recovered our wits, I jogged in place and watched it waddle away, naked tail dragging through the snow. I rubbed my gloved—and still cold—hands together and wondered, why the heck do opossums live in Wisconsin?
When I got home, some Googling revealed an interesting fact: Wisconsin is at the limit of the opossum’s geographic range. In turn, this got me wondering—what governs the limits of a species’ range?
Ecologists typically classify range-limiting factors as either abiotic or biotic. Abiotic factors do not involve living organisms; climate is the quintessential example. Biotic factors are interactions with other organisms. A classic example is competition between organisms, which is a direct biotic interaction. However, biotic interactions can also be indirect, such as when one species improves or degrades habitat for another. Abiotic and biotic factors usually work in concert to limit an organism’s range.
The opossum I saw behind Olbrich Gardens bespeaks both. Opossums, with their naked tails and ears, have a difficult time surviving cold environments. And yet, opossums live in snowy Wisconsin! However, this is a relatively new phenomenon—opossums did not occur in Wisconsin until the 1850’s, when their range expanded northward. The opossum’s conquest of Wisconsin has been aided and abetted by another organism, namely Homo sapiens. Humans provide extra resources (like trash), which help opossums survive Wisconsin’s cold winters. A biotic interaction has helped opossums overcome an abiotic limitation.
Regardless of the exact cause, opossums reach the northern limit of their range in Wisconsin. Several other species reach range limits in the state, a fact that can come in handy while classifying Snapshot Wisconsin photos. Look a photo’s metadata—what county was it taken in? In some cases, this can narrow down identification possibilities. For example, any rabbit-looking creature in Waueksha County is likely an eastern cottontail, since snowshoe hares do not occur in southern Wisconsin. A good source for species range maps is NatureServe Explorer.
For more information about opossums, see this recent Snapshot Wisconsin blog post by Emily Buege.
For more information about the opossum’s range expansion northward, I recommend reading Walsh and Tucker (2017).
Snapshot Wisconsin volunteers have identified a total of 493 triggers of weasels over the course of the project. Although we don’t distinguish between species in our classifications, Wisconsin is home to three distinct species: the long-tailed weasel, short-tailed weasel and least weasel. One of them is known as the smallest carnivore in North America, read through the post to find out which species it is!
The article below, “You little weasel!” by Christian W. Cold, was originally published in Wisconsin Natural Resources magazine in February 1998. After reading, you may find that these mysterious critters will weasel their way into your liking.
Survival is the objective of the day, every day, if you are little. And danger is always nearby when you are a weasel. Creatures larger than you are out there, listening, and watching with hungry eyes. You avoid their attention by remaining tentative; carefully choosing when to move. You travel about your 40-acre universe in a state of perpetual tension, keenly aware of every sound, every smell and every motion around you
Finding a meal is work. Avoiding becoming a meal is even tougher. As both hunter and hunted, you bear the risks by constantly moving. If you tarry, you die; if your prey hesitates, it dies. Your quarry takes many forms – most are smaller than you, but similar in appearance. Their scent lingers everywhere, but they vanish when you arrive. Your prey cringes in terror in your presence…with good reason
Weasels have an image problem. We are quick to condemn them as corrupt, greedy little villains who sneak around and kill with deadly efficiency for no reason whatsoever. We’ve historically viewed weasels as pests, varmints or scraps of fur only suitable for a decorative trim on collar or cuff. It’s a wonder that weasels have endured such a hostile world.In fact, weasels are marvelously successful. They persist by being alert, inquisitive, tenacious and most importantly, small.
Hunters of mice
Weasels are members of a large and diverse family of mammals known as mustelids, which include mink, martens, fishers and skunks. If you shake the family tree harder, badgers, wolverines and otters are also distant relatives. As a clan, the mustelids are typically slender, elongated animals with short legs, a small head and short fur. Their needle-like canine teeth are designed to pierce the throat and brain of small animals, particularly rodents.
The species name, Mustela, means “one who carries off mice,” and all weasels are accomplished mousers. However, to reap the benefits of their small, dynamic world, the weasels can’t afford to be picky eaters. The bill-of-fare includes chipmunks, ground squirrels, insects, small birds, frogs and snakes. Shrews form an important part of their winter diet. Though they occasionally eat fish, weasels are poor swimmers, paddling clumsily with their backs arched out of water.
Weasels have an earned reputation as fierce, efficient predators that will attack animals several times their own size. A four-ounce weasel can kill a four-pound rabbit. The weasel’s habit of killing larger prey and killing several animals at a time stems from its habit of storing or caching surplus food for later use.
Small caches scattered about can provide a series of small meals. Incidents of wholesale slaughter in poultry yards are likely triggered when a weasel goes into “hunt mode” in the unnatural setting of finding several confined prey with no avenue of escape
Three species of true weasels live in North America. The largest, at 18 inches, is the long-tailed weasel. Long-tails occupy diverse habitats throughout the United States and into Central America. They appear to prefer patchy landscapes of mixed habitats intersected by streams and small rivers. The smaller short-tailed weasel or “ermine” is found in heavily-forested areas and brushy areas of Canada, the northeastern states, the Upper Midwest and Northwestern forests. Smallest of the tribe is the least weasel, a pugnacious dynamo who claims the title as North America’s smallest carnivore. The least weasel is infrequently observed in the marshes and damp meadow. I once inadvertently caught one in a repeating mouse trp at the Mead Wildlife Area in Marathon County in the Upper Great lakes region.
The pelts of all three weasels are brownish and are replaced by a winter white coat that begins to appear by the first of November. The long-tail and short-tail sport a black tip on their tails; an attribute which may confound the striking accuracy of avian predators. Hawks, owls, eagles, foxes, coyotes, bobcats, lynx and domestic cats will eat a weasel – provided they can catch one! The larger mustelids such as mink, marten and fisher pursue small weasels with frightful determination. Size and agility are not the weasel’s only defense. A pungent musk, secreted from an anal gland, may repel or nauseate all but the most persistent of predators.
Weasels sexually mature before their first birthday. A typical litter of six or seven young is born each year and is cared for by both parents. Weasels reaching five to six years are regarded as fully mature. Individuals as old as 10 are considered ancient
How to find a weasel
Weasels are easiest to see in winter when leaf cover is gone and a thin layer of tracking snow will show their whereabouts in the neighborhood. Weasels leave staggered pairs of little footprints placed in a bounding gait fashion. Look for sudden right-angle turns in the tracks that often disappear beneath the snow and reappear at a considerable distance.
Weasels hunt aggressively during the cold, hungry months of winter. Their intense curiosity and insatiable appetite leads them to range widely in a seemingly erratic fashion. They seldom travel far in any one direction. A weasel will stop to poke its little head into every hole, nook and cranny it can probe. Its slender body can squeeze into lairs and runways of mice. Within these subterranean passages the weasel’s sensitive nose and ears will quickly locate the tenants.
Weasels often den in an abandoned (or usurped!) home of a chipmunk or ground squirrel, in a hollow log or under a pile of rubble. The nest chamber is often lined with fine grasses, feathers or the fur of the “former” occupants. Weasels are remarkably clean animals that will not defecate in their quarters. They designate a separate latrine area.
These sleek, little hunters are both feared and respected. If you are a weasel among mice, is it merely “a terrible efficiency” to be the animal that eats its neighbors? I think not. The weasel was designed by the limits of its environment to eat the flesh of others. It must kill to see another day. As humans, we tend to leave that grisly chore to the butcher, but the weasel assumes considerable risk and expends considerable energy just surviving.
The next time you get to see these ambitious little bundles of energy, take a moment to view the world from their perspective. Be thankful that at your comparative size, you can afford to wish them “good hunting.”
To view the full posting of the article in the Wisconsin Natural Resources magazine, click this link.