Ask a Naturalist – Why don’t birds’ feet freeze?


Written by Victoria Thompson, Minneapolis Park and Recreation Board Naturalist, North Mississippi Regional Park

You might not think of winter as a great time to see birds in Minnesota. After all, it gets so cold outside many people wish they had migrated south to warmer areas like so many birds. There are however, payoffs to braving the cold when winter bird watching. Sure, there aren’t as many types of birds around, but without leaves on deciduous trees, it’s much easier to see those that are here. And with winter’s later sunrises, getting up to see the dawn bird activity doesn’t happen at such a ridiculously early hour as in summer. Winter is a great time to casually watch birds and observe bird behavior with a smaller cast of characters. According to the Department of Natural Resources, there are 428 bird species that occur in Minnesota throughout the year; 44 of those are year-round residents. Many of our most commonly seen birds, such as cardinals, goldfinches, house sparrows, crows and black-capped chickadees stay all year.

It’s a common misconception that birds migrate south for the winter because it gets too cold for them. That can be true for some birds, but it’s not the main reason. Most birds, being well insulated by feathers, can withstand cold temperatures, but their food sources cannot. Insects are not active during our winters, so birds that depend on them, like warblers, must migrate to follow the food. The same goes for hummingbirds, which survive on flower nectar—no flowers in winter, no food for hummingbirds. And birds that require large areas of open water, like loons, also can’t stick around when our ponds, lakes, and rivers freeze over.

Not surprisingly, winter can be a difficult time for birds in Minnesota. The days are short, nights are long and cold, quality food supplies can be scarce with water and shelter hard to find too. How do the birds that stick around survive? How do they not lose all their heat and freeze to death? And while some owls have feathered feet, most birds don’t—if you look at their feet and legs, it’s just bare scaly skin. How do they not get frostbite?

The first line of defense against the cold for birds is feathers. Fluffing up feathers increases their insulation power by creating more air pockets that trap body heat, which helps keep the birds warm. If you look at birds in winter, they often look rounder because their feathers are all puffed up. Many birds also grow more down feathers for the winter months, similar to how some mammals grow a thicker coat in winter. Finding shelter against the elements, such as evergreen trees and bushes, is also an important heat saving strategy.

And then those scaly feet—why don’t they freeze? Strangely enough, bird feet can get really cold without causing them harm. First of all, there is little in the feet that can freeze—their feet are made up mostly of bone and tendon. Then, birds’ hearts beat so fast that blood circulates very quickly, and doesn’t stay in the feet long enough to freeze. Some birds will also perch on one leg while drawing the other in to the breast for warmth. Furthermore, there is a countercurrent exchange system in their feet. The blood vessels taking warm blood to the feet pass very close to the vessels taking cooled blood from the feet. The outgoing blood warms the incoming blood so that it doesn’t chill the bird’s core temperature. A very ingenious solution from Mother Nature! Winter birds, especially small ones, eat a lot in order to get the calories needed to produce enough body heat to stay warm. Increase your chances of seeing them by putting out high-fat, high-protein sources of food, like sunflower seeds and suet.

Join us for our monthly birding program on the first Saturday each month. This month we’ll be looking especially for some of our most entertaining winter birds—woodpeckers! Learn more about this and other programs and events, and free use of snowshoes on Sundays.

January Public Programs

January 2-4—Frozen Planet Camp: Adventure through the cold depths of outer space and conduct experiments for extreme environments. $90, ages 6-12, 8 a.m.-4 p.m.

January 5—Birding: Winter Woodpeckers. Join a naturalist to look for these vivid winter birds. Ages 8 and up, 4-5:30 p.m.

January 5—New Year’s Resolution Snowshoe Hike. Start that resolution off right by exploring the park with a naturalist. All ages, 1-2:30 p.m.

January 13—Family Funday: Winter Arts and Animals: meet animals up close and make art to take home. All ages, 1-3 p.m.

January 19—Nature Art: Candle Making: craft a candle with a nature twist to take home. $5/person all supplies included. All ages, 1-3 p.m.

January 26—Outdoors: Winter Survival Challenge: Practice your winter survival skills in the park! Then enjoy some hot cocoa and a treat by a cozy bonfire. All ages, 1-3 p.m.

January 25—Winter Fun and Games Camp: Explore the park, play games, make art and meet some local animals. $25, ages 6-12, 8 a.m.-4 p.m.

Every weekend, Saturdays 11 a.m.-3 p.m., Sundays 1-3 p.m.—Free Snowshoe Rental. Check out a free pair of snowshoes to explore the park! Please wear winter boots.

Find registration for these programs and more at or call 612-370-4844 for details. Do you have a question about nature in your own backyard? Then send it our way by emailing and it could appear in a future article. Like us on Facebook to stay in the loop about what is happening at your park!