Where do they go in the winter?
Tracks in the snow. ©A.Brennan
Winter is a time of incredible adaptation - from luna moths that wrap their cocoons in leaves, to frogs that freeze and thaw, animals have unique ways of surviving the cold.
Winter.
For some of us in southern Quebec it means sunny, crisp, snowy days filled with skiing, snowshoeing and a silence that can only be felt when the world is blanketed under a deep layer of snow. For others it means flannel pyjamas, hot chocolate, binge-watching favourite shows, and stepping outside only when absolutely necessary. And for others still, it means driving south for days on end to escape the freezing grip of the north and enjoy the easy life of t-shirt and snow shovel-free weather.
A snowy trail in the forest. ©A.Brennan
Our local wildlife share similar relationships with winter, only they come equipped with specialized biological traits to adapt in unique ways - some embrace the cold with thicker coats or wide feet, while others rely on antifreeze-like chemicals in their bodies or exceptional tunnelling and insulating skills to survive. And of course, some migrate south, following their instinctual path toward warmer climates.
Who embraces the elements?
For those of us who bundle up in snow suits and hit the trails with our cameras, excited to see the crystallized, leafless world, we are likely to spot some of our fellow cold weather residents that stay out year long;
Birds: Those that stick around will fluff out their feathers for added insulation and find ways to feed as efficiently as possible in order to conserve energy. Some have the ability to lower their body temperatures and many gather in flocks to share resources.
Acorn on ice. ©A.Brennan
Chickadees are scatter hoarders, storing food in tree bark cracks throughout the year. In the fall, their brains actually grow in size, so they can remember where their caches are (Smulders et al., 1995)!
Blue jays also scatter hoard, storing acorns everywhere they can. Many of these will remain uneaten, and become the next generation of oak trees.
Crossbills and cardinals have specialized beaks that make it easier to access nuts and seeds in the winter.
If we’re lucky, we might spot an owl, who’s most likely already spotted us from a perch on a branch or peeking out from within a tree cavity. Efficient hunters, they easily spot prey throughout the winter, and can even locate small animals in the subnivean zone (the layer between the snow and the ground).
Bald eagles and ravens act as the clean-up crew - animals that are lost to the harsh conditions will not go to waste. Shadowing wolves and other large carnivores, they will be nearby during a hunt and will wait their turn to share in the feast.
Mammals:
Foxes, wolves and coyotes grow thicker coats in fall to withstand the cold, and will hunt for small animals in the subnivean zone.
Snowshoe hare and lynx have large feet designed for travel in thick snow. They move silently and we rarely get to catch a glimpse of them.
Flying squirrels are nocturnal and brave the coldest temperatures - to survive this harsh environment, they nest together in tree cavities and form ‘cuddle puddles’ to share body heat (Overall, 2023).
River otters have thick, waterproof fur that protects them from the cold while hunting underwater. They create an access hole in the ice of a frozen lake or pond and maintain it throughout the winter.
Deer slow their metabolisms down to require less food, and they create trails between feeding and resting spots to minimize travel effort.
Insects:
Not many insects are able to withstand extremely low temperatures, but snow fleas have evolved to master this trait. They produce a glycine-rich antifreeze protein that prevents the formation of ice crystals, helping them avoid freezing while foraging (Mok et al., 2010). Look for them hopping around in sunny patches of snow.
Who hides from the cold?
More animals hide from the cold in this region than embrace it. Depending on the species, some hibernate (in true hibernation, brumation or torpor), while others live in the relatively warmer subnivean layer, sink to the bottom of a lake or river, or suspend development (diapause) until conditions improve. Here are just a few of the animals and their strategies used to survive the winter months;
Birds: Armed (or winged!) with the ability to travel, birds don’t have the need to hibernate. Many will enter brief states of torpor though, slowing their heart rate, breathing and body temperature to conserve energy.
Chickadees remain active throughout the year but enter torpor during cold nights to reduce their energy-burning physiological activity.
Mammals:
Bats and groundhogs are some of the only true hibernators in this region. They decrease their heart rate and lower their body temperature to just a few degrees warmer than their environment.
A fox hunting in the subnivean zone. Image by Neal Herbert via flickr.
Black bears don’t truly hibernate - they enter torpor, lowering their heart rate but maintaining their body temperature. They can easily awaken and are able to remain active if they find a reliable food source, like bird feeders and unsecured garbage.
Shrews, voles and mice live in the subnivean zone, where they forage on seeds, bark and plants. They create tunnels, complete with sleeping areas, food stores and ventilation shafts (Crick, 2014).
Amphibians, reptiles and fish:
Turtles enter brumation, a hibernation-like state for cold blooded animals, and overwinter in the muddy layer at the bottom of ponds and lakes.
Many frogs overwinter similarly to turtles, but some, like wood frogs and spring peepers, spend the winter under the leaf layer, freezing up to 65% of their bodies (Storey, 1990)! They produce an antifreeze to protect their cells and organs, but their hearts will stop beating, they will stop breathing and their brains will cease to function (don’t worry - they easily thaw in the spring!).
Toads overwinter in deep burrows below the frost line.
Snakes gather in underground hibernacula; many snake species overwinter in groups, remaining semi-active and bundling together for warmth.
Fish slow their metabolisms and dive deep into warmer waters to survive.
Insects: They overwinter in the stage that best suits their survival - egg, larva, pupa, or adult. They enter a state of dormancy called diapause, where their development is paused until environmental conditions improve in the spring.
Luna moth. Image by Sebastian Alejandro Echeverri via Xerces.
Praying mantids overwinter in egg form. Females lay the eggs on tree trunks and rocks before dying in freezing temperatures.
Woolly bears (the caterpillars of Isabella tiger moths) tuck themselves into the leaf layer for protection.
Luna moths encase their cocoons in leaves for protection, while swallowtail butterflies create chrysalids that mimic leaves for camouflage.
Some butterflies, like the eastern comma and question mark, overwinter in the leaf layer as adults, surviving thanks to their production of glycerol.
Bumble bee queens overwinter as adults, burrowing under leaves or just below the ground.
How can we help support overwintering residents?
Leave the leaves and stems.
Blue-stemmed goldenrod seeds. ©A.Brennan
Insects hide in the leaf layer to survive. They also provide nutrient rich meals for other winter animals.
Fallen seeds and berries provide a winter buffet for animals. Shrews, voles and mice feed on these in the subnivean zone and subsequently become food for larger mammals.
Cavity nesting bees overwinter inside the stems of perennials and shrubs in egg, larval or adult form.
Provide a source of water.
Animals expend extra energy when digesting snow and ice. Place shallow dishes of water outside daily, to provide an easy source of fresh water.
Provide habitat.
Many animals like owls, woodpeckers and flying squirrels rely on cavities in dead trees for shelter.
Coniferous trees and shrubs, such as hemlock, cedar, spruce and juniper, provide both food and shelter. A loose pile of branches can also provide shelter if conifers aren’t an option.
Native plants that produce fruit and seeds (like viburnums, Virginia creeper, ninebark and sumacs), help nourish animals throughout the winter.
Woody debris provides shelter for insects, including beetles and ants (which in turn, provide food for others!).
Allow for insulation.
To help animals survive on the ground, let leaves accumulate before the snow falls, and allow a deep snow layer to build up. Shovel paths only where necessary, leaving plenty of sheltered habitat for subnivean residents.
Bear-proof your yard.
A simple bear-proof design. ©A.Brennan
Locking garbage containers are essential for bear safety. If bears have easy access to food, they may delay hibernation, become aggressive or even be euthanized if they persistently approach humans.
Bears are also attracted to bird feeders, so delay putting them out until the snow and cold arrive.
Who packs their bags and heads for the beach?
The migrators seem to have it all - enjoying 3 seasons of Quebec beauty and ending it off with a season at the beach! Of course, this long distance travel comes with its costs and not all make it back home.
Birds: Since they have the ideal adaptation for travel, many birds migrate to warmer locations, using a combination of instinct, environmental cues and magnetoreception (Wiltschko & Wiltschko, 2019).
Common loons migrate to the Gulf of Mexico for the winter, returning to the same body of water each spring to reunite with their mate.
Hummingbirds are tiny but mighty, often flying non-stop across the Gulf of Mexico!
Insects:
The late summer generation of monarch butterflies are biologically primed for migration, flying up to 3500 km south to Mexico. They rely on fat reserves to fuel their journey there and back.
Dragonflies also migrate, but their round-trip journey spans three generations.
Migrating monarchs. ©P.Brennan
How can we help support migrating animals?
Late season heart-leaved asters. ©A.Brennan
Provide a variety of native plants.
Many insects are specialists, relying on specific plants to lay eggs or feed their larvae. By supporting their life cycles, we help boost migration success.
Plant late-season blooming plants.
Fall blooming plants like asters and goldenrods provide essential fuel for migrating insects.
Plant native fruiting shrubs.
Many native shrubs, like sumacs and viburnums, produce seeds and fruit, helping to fuel migrating birds.
Animal tracks in the snow. ©A.Brennan
Winter can be a challenging season for those unprepared for its harsh elements, but the resilience of the natural world shows us the beauty of adaptation and preparation.
Whether we enjoy skiing, cozying up indoors or escaping to warmer destinations, we can all take simple steps to help the wildlife around us not just survive but thrive in these cold months.
By doing so, we can make this season a little easier for all living beings, and perhaps find a little magic in the process!
Find out what steps you can take on your land to help support local wildlife!
Resources:
Ducks Unlimited Canada: Dragonflies and monarchs: multi-generation migrations
National Wildlife Federation: Offer Water to Wildlife in Winter
The Humane Society: What to do About Black Bears: What to do about black bears
University of New Hampshire: Leaving Leaves and Flower Stalks for Wildlife
Watersheds Canada: Plant Database
Xerces Society: Nesting Resources
References:
Crick, J. (2014). The Subnivean Zone, Life Under the Snow: Part 1. Michigan State University. Retrieved December 5, 2024, from https://www.canr.msu.edu/news/the_subnivean_zone_life_under_the_snow_part_1
Overall, A. (2023). Do animals hug? – your connection to wildlife. https://blog.cwf-fcf.org/index.php/en/do-animals-hug/
Mok, Y. F., Lin, F. H., Graham, L. A., Celik, Y., Braslavsky, I., & Davies, P. L. (2010). Structural basis for the superior activity of the large isoform of snow flea antifreeze protein. Biochemistry, 49(11), 2593-2603.
Smulders, T. V., Sasson, A. D., & DeVoogd, T. J. (1995). Seasonal variation in hippocampal volume in a food‐storing bird, the black‐capped chickadee. Journal of neurobiology, 27(1), 15-25.
Storey, K. B. (1990). Life in a frozen state: adaptive strategies for natural freeze tolerance in amphibians and reptiles. AJP Regulatory Integrative and Comparative Physiology, 258(3), R559–R568.
Wiltschko, R., & Wiltschko, W. (2019). Magnetoreception in birds. Journal of the Royal Society Interface, 16(158), 20190295. https://doi.org/10.1098/rsif.2019.0295