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Written by Emily Stone
Naturalist/Director of Education, Cable Museum of Natural History
I hear a lot about the worries of people who are feeling lonely this winter. This time, they no longer feel like they’re trapped on icy roads and constant snowstorms. If anything, I miss my feathered friends! Due to a variety of factors, including good weather, you may find that there aren’t as many birds at your backyard feeder as usual.
My guess is that if the snow is shallow, many birds will be able to find food in the forest. Additionally, the milder temperatures require fewer calories to keep your body warm. In addition, our favorite species of grasshopper, red-billed flycatcher, and crossbill are “destructive species.” “Interrupt” means suddenly entering the area (as opposed to lava suddenly erupting from a volcano). We don’t see these invasive species every winter. At least not that much at all. Most migration is driven by food availability, and this is no exception. Their favorite foods will be even more plentiful elsewhere this year.
Siskin is the exception, at least at my feeder. The small striped finch with yellow highlights breeds in Canada as well as in remote forests of northern Wisconsin and Minnesota. Typical winter food shortages in the north can cause siskins to flock to New England, the upper Midwest, and even the southeastern United States. They seek abundant seeds of pine, cedar, larch, hemlock, spruce, alder, birch, and maple. I’m not sure what kind of natural foods will be plentiful this year, but my many siskins are enjoying a “sunflower chip” mix containing both shelled and whole sunflower seeds. it seems like.
In fact, I observe that Siskins are the most predominant bird at my feeders. They hiss and aggressively spread their wings to ward off goldfinches, black tits and nuthatches swooping in for the delicious sunflower seeds.
By eating all of these seeds, the pine siskin stores 50% more fat in the winter than its cousins the loggerhead and stonefinch. Small birds do not store fat in their adipose insulating layers like penguins and whales. They store brown fat around their wishbones and abdomen as a ready source of fuel for their metabolism. Siskins also store bedtime snacks within their esophagus, an expandable section called the “crop.” But it’s more than just a cookie and a glass of milk. Their crops can store seeds equivalent to 10 percent of their body weight.
![](https://tomahawkleader.com/wp-content/uploads/2024/02/NATURE-Emily-Stone-Pine-Siskins-1-240228.jpg)
With these calories, you could survive five or six hours at sub-zero temperatures. They can survive nights of minus 94 degrees Fahrenheit by increasing their metabolic rate to five times the normal rate for several hours. This is he 40% higher than other songbirds.
Why don’t more small birds gain so much fat in preparation for winter? Being too fat can make flight difficult, energetically costly, and reduce your ability to escape from predators. Black-capped tits can reach 10% body fat in winter. Instead, chickadees store food. They cache up to 100,000 groceries a year, most of which is done in the winter. To remember all these caches, the chickadee adds a new neuron for each hidden seed, fruit, and insect. As a result, the brain volume increases by 30%, but in the carefree days of summer it shrinks again.
In addition to adding a small amount of fat and more neurons, chickadees grow 12% more feathers for winter insulation. This is nothing compared to the common redwing, which has 31% more feathers. That’s a big increase for a bird that originally weighed only half an ounce. Why don’t more birds grow so many feathers? At the Wild About Winter Ecology Workshop a few years ago, University of Oshkosh professor Sheldon Cooper compared feathering a small bird to dressing a toddler in warm clothing. Larger creatures like snowy owls and adult humans can move fairly well, even with added puffy layers. However, the smaller they are present, the more likely these layers will impede movement.
Just like this strangely warm winter we’re having, every winter adaptation, from fat to feathers, has its pros and cons. If birds make you feel lonely, take advantage of the empty roads and visit your human friends instead.
Author’s note: Portions of this article were republished in 2014 and 2019.
Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available for purchase at: www.cablemuseum.org/books Even at your local independent bookstore.
The Cable Museum of Natural History has been connecting people to the Northwoods for more than 50 years. Our exhibition “Northwoods Rocks!” Winter and Spring Event Calendar is ready for registration. Follow us on Facebook, Instagram, and YouTube. www.cablemuseum.org To see what we’re going to do.
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