How animals survive the winter

Guest post by April Vaos

Living in Illinois, we’re lucky enough to enjoy a change of seasons. Though I often find it difficult to switch from the crunch of fall leaves to the crunch of snow, it can be a peaceful time to head outdoors. Recently, I went walking in Independence Grove in Libertyville, part of the Lake County Forest Preserves in northern Illinois. As I looked around in the quiet, contemplative landscape, I thought about the life that teemed all around me, and how it was now hidden from view or departed on a migration.

While leading winter walks, I’m often asked, “Where are all the animals?” It depends on the animal. Each employs different survival strategies that help it adapt and even thrive in winter. What, exactly, do animals do to make it through the challenges of cold temperatures and a lack of food? Well, I like to say they have MAD strategies: migrate, active and dormant.

When cool temperatures arrive in northern Illinois, so do dark-eyed juncos (Junco hyemalis). Not only do they visit Illinois, they migrate into all of the lower 48 states to spend a milder winter than where they’re from: Canada. Stock photo.
When cool temperatures arrive in northern Illinois, so do dark-eyed juncos (Junco hyemalis). Not only do they visit Illinois, they migrate into all of the lower 48 states to spend a milder winter than where they’re from: Canada. Stock photo.

Migrate: Many animals in Lake County migrate, or travel, from one place to another over short, medium or long distances to survive winter. It isn’t so much about the cold as the lack of food in winter. Food sources such as insects, plants and fish—which can’t be reached when waterbodies are frozen over—are largely unavailable.

Birds, butterflies and even bats are common migrators. Though we often think of animals migrating across hundreds or thousands of miles to different states or countries, they can also migrate short distances vertically. For example, some amphibians and insects burrow further down the soil horizon below the frost line to stay warm.

Lots of folks marvel over the long migration of monarch butterflies (Danaus plexippus), but hoary bats (Lasiurus cinereus) make extended flights, too. It’s believed that Illinois’ hoary bats migrate to southern California or Mexico for the winter, a 1,200-mile trip each way!

Hoary bats (Lasiurus cinereus) migrate to warm, southern locales for the winter. Photo © Merlin Tuttle.
Hoary bats (Lasiurus cinereus) migrate to warm, southern locales for the winter. Photo © Merlin Tuttle.

Active: Some animals remain active during winter. Doing so means they need to find food continuously to survive. To endure the weather, they may grow extra fur or build winter homes. Examples of animals that stay active include white-tailed deer (Odocoileus virginianus), coyotes (Canis latrans) and even channel catfish (Ictalurus punctatus).

Northern cardinals (Cardinalis cardinalis) are both the Illinois state bird and a great example of an active winter animal. Cardinals are permanent residents, forgoing southward migration. Due to the cardinal’s varied diet of seeds, fruits and insects, they can find enough food in Lake County year-round. While often called warm-blooded, a better term is endothermic, meaning cardinals can produce their own body heat.

Northern cardinals (Cardinalis cardinalis) are red year-round. They get their color from carotenoid pigments in the seeds and fruits they eat. Stock photo.
Northern cardinals (Cardinalis cardinalis) are red year-round. They get their color from carotenoid pigments in the seeds and fruits they eat. Stock photo.
During winter, red foxes (Vulpes vulpes) practice a hunting technique called mousing. Fox ears are sensitive to the quiet sounds that prey animals make as they chew or move around beneath the snow. When a fox locks on to a vole or mouse, it pounces, punching through the snow headfirst, trying to snap up its prey. Stock photo.
During winter, red foxes (Vulpes vulpes) practice a hunting technique called mousing. Fox ears are sensitive to the quiet sounds that prey animals make as they chew food or move around beneath the snow. When a fox locks on to a vole or mouse, it pounces, punching through the snow headfirst, trying to snap up its prey. Stock photo.

Dormant: Dormancy describes a period when an animal’s metabolic activity is minimal and development is temporarily suspended to conserve energy. This allows species to prosper in environments where they might not otherwise be able to survive.

There are varying degrees of dormancy. Hibernation is full winter dormancy, which can last all season and includes decreased body temperature, heart rate and metabolic rate. Groundhogs (Marmota monax) and thirteen-lined ground squirrels (Spermophilus tridecemlineatus) are hibernators. On the other hand, torpor, a deeper sleep than normal—as seen in black-capped chickadees (Parus atricapillus) and deer mice (Peromyscus maniculatus)—may only last a few hours. These animals are active in warmer weather but may enter torpor daily or during bouts of extreme cold.

Groundhogs (Marmota monax) are skilled at surviving winter through hibernation—but contrary to popular culture, they don't have the ability to predict weather or the severity of the winter. Stock photo.
Groundhogs (Marmota monax) are skilled at surviving winter through hibernation—but contrary to popular culture, they don’t have the ability to predict the severity of the winter. Stock photo.

Wood frogs (Lithobates sylvaticus) have an almost zombie-like adaptation. In fall, a wood frog finds a safe spot under a log or leaf litter. When the temperature in its home falls below 32 degrees Fahrenheit, the frog starts to freeze. This prompts its liver to convert glycerol into glucose, forming a sort of antifreeze. If you were to find a frozen wood frog, there’d be no heartbeat or breathing motion to tell you it was alive. But come spring, this hardy critter will thaw and hop away as if it never became a frog-sicle.

It’s interesting to note that most animals don’t have just one, but multiple strategies for outlasting winter. Blanding’s turtles (Emydoidea blandingii) are cold-blooded—or ectothermic—so they depend on the sun’s rays, plus air and water temperature, to keep their body temp ideal. For the winter, a Blanding’s turtle migrates down to the bottom of a wetland and buries itself in mud. Once safe and sound, it enters dormancy.

Looking for a way to not just survive but thrive this winter? Venture out for a hike with our Animals in Winter program on January 15, 2022, 1-4 pm. Or learn to decipher animal tracks by taking our Winter Tracking and Wildlife Observation Workshop program on January 29, 2022, 9:30 am-12 pm.

Whatever you choose, I hope you get outside this winter and enjoy the serenity of the season, knowing that many animals are hunkered down for the time being—just waiting for spring to return.

Flicking through the Flickr pool

This gallery contains 10 photos.

Post by Brett Peto

You don’t need me to tell you that 2020 has been a long year. In a pandemic, separated from routines, sometimes days go slow but months go fast, and vice versa. There are fewer anchors around which to pin our schedules like so many pieces of laundry on a clothesline. Some people have started baking homemade bread, assembling model kits, binging movies and podcasts, devouring piles of books, or playing long-distance board games over Zoom. Our strategies may vary, but I think it’s helpful to have as many coping mechanisms as we can gather this year.

One adopted or continued by many folks is spending more time outdoors. Whether in yards, neighborhoods, parks, or the Lake County Forest Preserves in northern Illinois, people are discovering or rediscovering the value of nature, even as the thermometer dips. Fresh air; sunshine; wide horizons; the sounds of wind in trees and water over rocks; birds and squirrels and foxes living their private lives; the calm curiosity to find out where a trail goes and the confidence that it’s designed to go somewhere.

"Ice Ice Baby." Photo © Michelle Wendling.
“Ice Ice Baby.” Photo © Michelle Wendling.
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Finding the right angle

This gallery contains 10 photos.

Post by Brett Peto

I keep thinking about angles. Not the kind you measure with a protractor, but those you measure with your mind. The angle of a story, a conversation, or a project. Photography, of course, uses physical angles—where’s the camera pointed? is the sun directly overhead or is it the sweet time of golden hour?—but the best photos make you want to see even more. They make you want to break open the frame and soak in every bit of the Lake County Forest Preserves in northern Illinois.

Since it’s nearly the end of 2019, I thought I’d turn 180 degrees and peruse the photos uploaded to our group Flickr pool since January 1. Suffice to say: we’re spoiled. Spoiled with the beauty of Lake County’s flora, fauna, and natural areas, and the talent of the photographers who capture it for everyone to see. Trees and shrubs in their bright fall wardrobes on either side of a trail draining into a vanishing point. A sandhill crane (Grus canadensis) with both wings up like a paper airplane as it dashes to take off. A whirlpool of stars spun around a rich blue sky over a tranquil wetland.

I’ve gathered these moments plus seven more below, but that’s only a small taste. I encourage you to browse the rest of the visual buffet as we make the turn out of the 2010s into the 2020s. And, hey! You might become inclined to upload that shot living on your phone, camera, or computer.

"Night Moves." Photo © reddog1975.
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A walk through winter

Post by Brett Peto

I started my position with the Lake County Forest Preserves in northern Illinois in 2017. By the end of 2018, I had visited 45 of our 65 locations. Each time I returned from a new spot, I circled it on a map at my desk. Their names were just as diverse as the habitats within. Old School, Lakewood, Middlefork Savanna, Singing Hills, Cuba Marsh. Oak woodlands and savannas, prairies, sedge meadows, marshes, wetlands.

In mid-January, it felt like a good time to circle another name: Heron Creek in Lake Zurich, Illinois. It surprised me that I’d never walked its trails. A 242-acre preserve home to rolling woodlands, fields, the Indian Creek basin, and more than 116 species of birds, Heron Creek is closer to our General Offices than several sites I had been to. It was even roughly on my route to and from work. So toward the end of January, I took myself, some winter weather gear, and a few cameras there to explore.

A snow-swept field at Heron Creek on January 22, 2019. Photo © Lake County Forest Preserves.

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Time to make a moment

This gallery contains 18 photos.

Post by Brett Peto

Time can never be stopped, sped up, or slowed down. It started long before now and will continue far after. But with photographs, we can pause time, pin it in front of us, and study reality. It’s like kneeling at a riverbank and scooping a handful of water. The current stops in your palm, but just a foot beneath it carries on. Photos take time to make a moment.

With nearly 31,000 acres to explore, many moments are possible in the Lake County Forest Preserves in northern Illinois. An eastern bluebird (Sialia sialis) landing with one foot, wings at sharp angles. A cluster of milkweed seeds hanging on to their pod by threads of floss. Sunflowers and sunbeams, two shades of honey mixing in the air. I’ve collected these special moments and more in a gallery below.

All photos featured were taken by the truly skillful photographers in our group Flickr pool. Each of these images, these presses of the pause button and scoops out of the river, were captured in 2018. Our sincere thanks go to every photographer who shares their time and talent documenting the flora, fauna, and natural areas of Lake County.

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Halloween Hikes—30 years and counting…

Post by Jen “Blanding’s Turtle” Berlinghof

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This year marks the 30th anniversary of the Lake County Forest Preserves’ popular Halloween Hikes at Ryerson Conservation Area. This event is a witch’s potion of sorts: a dash of theater, a drop of night hike, a splash of environmental education, and a heap of old-fashioned family fun. Continue reading

A year in photos—2015

Gallery

This gallery contains 27 photos.

Post by Allison Frederick As the year draws to a close, it is a great time to celebrate the biological diversity protected within the Lake County Forest Preserves in northeastern Illinois. I have compiled some amazing photographs that were captured right here … Continue reading