Staying Warm in Winter

With so much of the US in a deep freeze this week, we got to thinking: how do our wildlife stay warm in the winter? Because it was COLD at Cedar Creek and in the rest of Minnesota this week. Cold enough that our local school districts - including the University of Minnesota! - were closed for multiple days, cold enough that International Falls, MN ("the Nation's Ice Box") set a new daily temperature record, cold enough that the Postal Service suspended mail delivery for two days. With air temps in the -30s and -40s Fahrenheit and windchills reaching into the -50s and below, most human Minnesotans put on extra layers and holed up inside in front of their fireplaces (especially after a statewide alert to turn down the thermostats and conserve natural gas). What about the birds and wolves and bison though? Will there be ANYTHING on the Eyes on the Wild cameras after a deadly cold spell like the one we just went though? Luckily, the answer is a resounding yes. Below are links to a few resources explaining how our wildlife weathers this arctic weather!

A red-headed woodpecker stocks up in the wintery oak savanna at Cedar Creek. 
Photo by citizen scientist Siah St. Clair.

Birds
About half of the birds commonly seen in Minnesota actually spend the winter here! Minnesota Public Radio recently dug into their strategies for dealing with sub-zero temperatures. You can read it here!

Naturalist and writer Bernd Heinrich also does a great job of explaining some of the incredible adaptations birds in Minnesota and elsewhere have for surviving wintery weather: countercurrent exchange to prevent frostbite, shivering, flocking, gorging and snow-burrowing! His wonderful piece, with illustrations by Megan Bishop, can be read here.



Deer
Like birds, deer have a variety of adaptations to help them stay warm. They shed their thin summer coat in the fall and replace it with winter pelage make up of hollow, insulating guard hairs. You've probably noticed this transition on the cameras! They also gather together and rely on one another's body heat to stay warm during the deep freeze, and change their diet to protein-rich nuts and seeds when they can. You can read a bit about their strategies here.



Canids
Wolves are so well-insulated that snow doesn't melt when it lands on their fur. It also doesn't melt underneath them when they sleep in the snow - they compact the snow but that's it! Our friends at the International Wolf Center in northern Minnesota put together this kid-friendly PDF about wolves' winter adaptations.

As you may have noticed, our two fox species both have very long, very bushy tails. These are a huge help in the winter, when they can wrap them around to keep their faces wrong! Doesn't that sound cozy? You can read about other adaptations foxes have for winter life here, including some beautiful pictures of them hunting in the snow!

Bison weathering the chilly temperatures at the NorthStar Ranch in Wisconsin.

Bison
Bison are incredible. They are massive creatures that subsist on grass, and they are built to withstand blizzards on the Great Plains without batting an eye. The National Parks Service calls them "the winter survivor", while the World Wildlife Fund details how they use their massive heads as snowplows to get to buried vegetation underneath. Cedar Creek's bison herd is only onsite during the summer, but how cool would it be to see that behavior on the cameras! The family we borrow our bison from, NorthStar Bison in Wisconsin, shared recently that studies have shown bison don't even start to notice the cold on their skin until around -60°F.

A bear den at Cedar Creek, located by citizen scientists on the January Wildlife Survey.
Photo by Jon Poppele.

Black Bears
We're lucky to have renowned black bear researcher Sue Mansfield classifying pictures along with the rest of us on the project! With luck, we'll be able to convince her to come out of retirement and write us a whole blog post about bears! In the meantime, you can read up on some of the species' winter behaviors and strategies, courtesy of Sue's old haunt, the North American Bear Center in Ely, MN. (more interesting articles about hibernation collected here!) One thing that will make you respect bears this time of year - they give birth in their dens in late January and early February aka RIGHT NOW. When it's -10000° (more or less)!


The good news is that it's up to 0°F this morning already, headed for a high in the upper 30s (ABOVE!!) on Saturday and Sunday. It's a bit of a weather rollercoaster, but I'm looking forward to seeing folks in t-shirts and the wildlife out enjoying themselves!


Want to learn more about how animals survive winters in Minnesota? The Star Tribune did a nice article a few years ago that covers some additional species you may be wondering about. Stay cozy everyone!

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