Birds Brave the Cold All Day and Night. How Do They Do it?
Ava Michelangelo and Maggie Watson, teacher-naturalists at the Milford Point Coastal Center, produced an Ask the Naturalist video recently about how birds keep warm in winter. A reporter emailed Ava last week asking the same question, plus a few others.
It seemed like a good time to share the questions and the video again. Then keep scrolling for important tips about providing food and water (absolutely essential) for birds in cold weather.
Q: Many people worry about birds’ well-being when temperatures drop. How do birds survive freezing conditions?
Ava: This is a question we get quite frequently. I think it’s because we cannot imagine spending all day and night braving the cold ourselves, so we have empathy for these animals that have to.
In reality though, birds have quite a few ways to stay warm. For example, their feather density increases anywhere between 35-70% in the colder months. So just like how our attire goes from t-shirts and shorts in the summer to jackets and long pants in the winter, these birds go through a similar change.
They can also be seen “tucking,” which is when they tuck their head under their wing to breathe that warm air in between their feathers.
The list goes on, but these are a few that can be observed next time you watch birds out in nature or from the comfort of your warm home this winter.
Q: Are some species better equipped than others for very cold weather?
Ava: Of course! The birds that we see year round in Connecticut, like the Black-capped Chickadee, are species that do really well here in winter. You could think of them as high energy birds. They are constantly shivering to generate heat while searching for high fat foods like seeds.
My favorite fact about chickadees is that their hippocampus, the part of their brain that stores memories, is larger in the winter. This helps them remember where they have cached their food. I’d say that makes them a well equipped bird for the cold months when food may become scarce.
Q: What’s the weirdest or most surprising way you’ve seen a bird stay warm? Have you ever witnessed winter behavior that made you laugh or stop in your tracks?
Ava: The first bird that comes to mind is the American Black Duck. Where I work, at the Coastal Center, black ducks can usually be spotted any day of the year. On the days that the salt marsh is frozen over, you’ll still find these birds resting on the frozen ice!
They, along with most waterfowl, have what is called a countercurrent heat exchange system in their legs which keeps their blood flow warm as it travels back to their heart. Birds are so incredible!
Q: What’s the coldest day you’ve ever spent observing birds, and how did they handle it?
Ava: Each winter, my colleagues and I participate in a Christmas Bird Count (CBC) which is an annual bird census. We are usually out birding from dawn to dusk when the weather permits. In most cases, these birds will be totally unphased by the cold, but on days with a wind chill of -6°F like the CBC of 2024, some birds will likely be taking shelter too (just like we did soon after).
Blue Jays are frequent winter visitors to bird feeders.
Tips for providing food and water for birds in winter
Most birds that stay in the area during the winter are seed eaters. So winter is when it is particularly important to fill feeders and keep them filled.
To maximize the number of species that visit your feeders, you’ll want to offer a variety of seed. Specific feeders are designed for specific seeds so be sure you have the correct seed for your feeders.
Bird Seed
Birds need extra energy and fat reserves to keep warm and sustain life during the winter’s cold and food-scarce conditions.
During the day, birds spend their time eating continuously so they’ll have enough calories to keep warm at night. Fat provides an excellent source of energy for birds. Suet and seeds high in fat, such as sunflower seeds and nut blends, are excellent choices for your feeder.
Black-oil sunflower attracts numerous species in winter. These seeds have a high meat-to shell ratio, they are nutritious and high in fat, and their small size and thin shells make them easy for small birds to handle and crack.
The indigestible husks tend to end up on the ground under the feeder, so some people prefer to buy sunflower hearts, which come without the husks.
Safflower seeds are another good choice, as is a high-quality mix containing sunflower, white millet, safflower, and peanut hearts.
Water
In the winter it is particularly difficult for birds to find unfrozen water. Birds need water not only to drink but also to bathe in — clean feathers provide the best insulation.
Providing a dependable supply of fresh water will even attract birds to your yard that wouldn’t ordinarily come to your feeders.
To keep your bird bath free of ice, you can buy a bird bath heater or heated bird bath that you plug in. Another option is to paint the inside of your bird bath flat black (with a toxic-free/food-safe paint) and place it in a sunny place out of the wind. You’ll be surprised how long it stays ice free.
Where to Place Your Feeder
The best place for your feeder is anywhere that has some shield from gusty winter winds.
Feeders should be placed in a sunny area about 8 – 10 feet from shrubs or evergreens where birds can find shelter from bad weather and easily see predators.
Birds have distinct preferences for heights and types of feeders, so place your feeders in different locations around your yard to reduce overcrowding. If all your feeders are in one area, a dominant species will keep the others away.
Remember that windows are a particular hazard to birds. Information on how to make your windows bird-safe can be found here.
