 January 2023
While some wildlife migrate to warmer regions in winter, others hibernate, change their furs or freeze.
Many creatures — like chipmunks, hummingbirds, woodchucks, bees, snakes, bears, skunks and opossums — enter states of winter dormancy to conserve energy. This is typically called hibernation. Hibernation is a type of winter dormancy where body temperature, heart rate, metabolic rate, and/or breathing rate decline. But each species hibernates in its own special way.
Weasels, hares, and jackrabbits change their coats to white to blend in with their snowy surroundings. Fish congregate in deeper, warmer waters. Some amphibians freeze for the winter.
Some humans choose to stay inside. But we hope you, our loyal readers, stay active and discover the wonders of winter outdoor recreation and wildlife viewing (scroll down for insider tips from our park naturalists!).
Special gratitude and a shout-out to our friends in the Nongame Wildlife Program (of Eagle and Falcon Cam fame) who collaborated with us on content for this Trailblazer issue.
Amphibians and reptiles are famously cold-blooded or "ectotherms," which means they depend on the environment to regulate body temperature.
 On summer evenings, look for the gray treefrog by your window, feeding on bugs attracted to the light inside.
Spring peepers, some gray treefrogs (pictured) and wood frogs spend the winter in a partially frozen state under fallen leaves, rocks or logs. Their livers convert glycogen into glucose (wood frogs) or glycerol (spring peeper and gray treefrogs) to produce an antifreeze to keep liquids from freezing inside their cells, while allowing ice crystal to form between layers of skin and muscle. They stop breathing and their hearts stop beating.
More about wood frogs from the National Park Service.
Turtles adjust their body temperature to their surroundings and can drop it as low as 39 degrees Fahrenheit.
 The snapping turtle is Minnesota's largest turtle.
Many Minnesota turtles survive the winter underwater or mud. Within hours of being underwater, a turtle’s blood oxygen levels drop to near zero, when they rely on cloacal respiration. The blood vessels around the cloaca (butt) are able to take up oxygen directly from the water. If oxygen is depleted, snapping and painted turtles can switch to anaerobic respiration, which is a form of breathing that does not require oxygen. This can cause lactic acid build-up, which turtles neutralize with carbonate buffers... and plenty of basking in the springtime sun to increase metabolic rate and get rid of acidic by-products.
Source and more information: How do turtles survive the winter? from Carleton College Cowling Arboretum website.
Many songbirds have migrated south of Minnesota for the winter. But some songbirds migrate south *to* Minnesota!
Snowy owls (pictured) nest in the Arctic tundra of northern Canada and Alaska during the summer. From early November to late March, some migrate south to Minnesota to hunt voles, mice, and other small animals. Look for them in northern Minnesota in large, open areas (like fields and airports), or perched on the ground, on buildings or on utility poles.
Snow buntings have adapted to thrive in winter environments. Their dense white feathers, which cover them from bill to ankles, and a lower body temperature help them fend off hypothermia. They migrate from the Arctic to spend October through April wandering the northern Great Plains, looking for food by lake shores, grasslands and farm fields.
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 Click on the photo to read about golden eagles wintering in Minnesota on the Minnesota Conservation Volunteer magazine.
Golden eagles also migrate from Canada, some from as far north as the Arctic Circle, and spend November through March hunting turkeys and fox squirrels in central and southeast Minnesota. Golden eagles can be hard to distinguish from young bald eagles, but there are subtle differences.
Head to Wild River State Park with a pair of binoculars and a warm coat, and follow naturalist Sean Hoppes' tips for a chance at spotting the emblematic national bird.
 Lead poisoning is a major threat facing Minnesota’s bald eagle population today. Learn more about bald eagle recovery efforts in Minnesota.
Only a few decades ago, bald eagles were hard to find. Thanks to conservation efforts, they have reoccupied much of their former range across Minnesota. Wild River State Park is a fantastic place to spot bald eagles. Start from the Visitor Center and walk or snowshoe the one-mile Amik’s Pond Loop for a good chance at a sighting. Scan the forest for a large collection of sticks – that's a bald eagle's nest! The trail skirts the edge of the St. Croix River for a brief distance. Look across the river to Wisconsin for another eagle viewing opportunity.
By February, the nest will likely have eggs, and the parents will diligently warm the developing chicks with their body heat.
Southeastern Minnesota is another great destination for birders and bald eagles alike. The best eagle sighting opportunities are between December and March. The current of the Chippewa River flowing into the Mississippi maintains open water throughout the winter where eagles soar and dive for fish.
The trumpeter swan is the largest waterfowl in North America and the largest swan in the world. Want to know how to identify it? Naturalist Kao Thao gave us the scoop.
 Did you know all wild swans are protected? PHOTO: Travis Novitsky
The number of trumpeter swans wintering at Fort Snelling State Park has increased through the years. As early as October, the large white waterfowl start showing up at Snelling Lake, individually or in small flocks. The spring and aeration system on the west end of the lake keep a small area from freezing over, allowing waterfowl access to water and food during winter. Trumpeter swans can be distinguished from other waterfowl by their large body, long neck, white plumage and almost solid dark “duck” bill. They lack the yellow marking under the eyes found on tundra swans.
Spot them from your car from the main road between Snelling Lake and the Minnesota River or walk the Snelling Lake trail along the holding ponds.
Kurt Mead, naturalist at Tettegouche State Park, told us otters have winter superpowers. Who knew?
River otters have a special coat of fur to keep them warm in winter. Their fur consists of two layers, one for warmth and the outer layer for waterproofing. This layer of insulation also allows otters to swim in frigid waters, which is important for maintaining their diet of aquatic critters like fish, crayfish, and clams.
River otters have another superpower in the winter: They can slide on their bellies across the snow to save energy when the snowpack gets deep. North Shore rivers often show signs of their "hop, hop, slide" behavior as they move from one open river pool to another. Lots of other mammals use these open corridors for easy passage in the winter so it's anyone's guess whose signs of activity you see in the snow on frozen rivers.
Whatever you do, don't follow the otters! River ice can be unpredictable and dangerous. Always be careful when venturing on frozen water.
Learn about restoration efforts to get river otters back to southwestern Minnesota from the MCV.
The white landscape is the perfect backdrop for viewing wildlife, especially those with orange-red coats. Naturalist Christa Drake shared how red foxes use their keen ears for hunting.
 The red fox can run as fast as 30 miles per hour, and can leap 15 feet in a single bound — farther than a kangaroo. It is one of the few predators that store food items for future use. PHOTO: Travis Novitsky
Each winter, red foxes can be seen at Lake Bemidji State Park near roads, by the bird feeders, in the campground and along the lakeshore hunting for squirrels, rabbits, shrews, mice and other rodents. These canines are known to have excellent hearing and can locate prey up to one hundred feet away and even under the snow! A red fox will listen closely for the faint squeaking of a mouse, pinpoint where the sound is coming from, jump into the air and pounce into the snow to catch their prey.
Did you know North American porcupines are active year-round? Naturalist Erin Fallon has tips for spotting the prickly rodents or, at least, signs of their activity.
Mille Lacs Kathio State Park is a great destination to observe porcupines during winter. Mainly busy at night or twilight, they can also be seen during the day on the ground or high in trees. As you travel along the Touch the Earth Trail, look for scat or tracks or trees with missing bark (which porcupines eat). Their tracks are long and oval-shaped with pebbled pads, and with or without inward pointed toe and claw marks.
Porcupines staggered gate causes them to travel rather slow. What they lack in speed, they make up for with their strong defense in the form of long, barb-tipped quills, for which they are named: Their name derives from Latin for "quill pig."
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The water in the spring-fed streams of the Driftless Area stays at a fairly consistent temperature of 48 degrees Fahrenheit. Sara Holger, naturalist at Whitewater State Park, recommends trout-watching or fishing!
 Nestled in the blufflands of southeastern Minnesota, Beaver Creek Valley State Park is known for its clear streams fed by the "Big Spring."
Streams in southeast Minnesota rarely ice over. If you approach the running streams slowly and quietly and without casting a shadow on the water, you may see sluggish trout gathered in deep pools. The fish slow down during winter as their body temperatures drop and food becomes more difficult to find.
Trout fishing is open year-round in Beaver Creek Valley, Forestville/Mystery Cave and Whitewater state parks, with catch-and-release season in winter. Be careful along stream edges as snowy banks can hide thin ice and water below.
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