How Do Birds Deal with the Cold?
It has been snowing for two days at The Cove with single digit temperatures and as rangers have been plowing and shoveling, wearing several layers of clothing, we are still freezing. As I look around the only living things out here that are up and moving around are birds. There are a lot of different birds at The Cove and only some migrate to warmer climates in the winter. Yesterday I saw Canada Geese, various ducks, Red Tailed Hawks, a Bald Eagle, a crow and numerous American Robins out hunting for food. Have you ever wondered how they cope in the winter? You’ll be amazed at the amazing adaptations birds have to stay warm and survive the frigid temperatures.
When the temperature drops I crave warm, hearty, calorie laden foods. These foods mean packing on the calories, which I’ll have to deal with in the spring, but birds need to increase their caloric intake too. Birds put on fat as both an insulator and energy source: More than 10 percent of winter body weight may be fat in certain species. It’s important to remember this can only be done in small amounts since they are a flying animal and still need to be able to take off. As a result, some birds spend the vast majority of their day time hours seeking fatty food sources. They are adapted to find, store, and remember where the food is so they can find it quickly. This makes winter foraging super efficient.
Birds have to work smarter not harder in the winter. One of the most effective strategies for having enough energy from food to stay warm is to not do highly energetic things during the cold season such as defend territories, spend a lot of time singing (although the Geese are constantly honking!), don’t build or maintain nests, don’t produce eggs or have hungry chicks around.
Birds of prey highly detailed knowledge of its home range and patience can mean the difference between life and death. During a short break in severe weather, a Barn Owl can fly directly to the best foraging habitat in any given ground, light and wind conditions. They are more likely to hunt from a fence post than from the air; this saves energy that would be used in flight and reduces heat loss.
Since birds can’t fly over to their closest Patagonia store or order a jacket from L.L. Bean, they have to find other ways to keep warm. Here is a list of some of their other adaptations:
- During the day time they soak in the sun.
- “Feathers are incredibly specialized structures that serve many purposes including, for many species, keeping them warm,” says Peter Marra, head of the Smithsonian Migratory Bird Center at the National Zoo. Larger birds like geese will grow extra feathers. All their feathers help keep them warm, but especially the downy under feathers and act like tiny little North Face down coats. Bird feathers are also covered in oil which makes them waterproof.
- Smaller birds seek out dense foliage or cavities in rocks to avoid the elements and lessen wind-chill.
- Bird feet are covered with scales and have very little cold-damageable tissue in them. They are mostly bone and sinew. This minimizes the likelihood of frostbite. Bird feet are generally grabbing at rest, so it takes very little energy to stay attached to a branch.
- Ducks in Upper Deschutes huddle, bunching together to share warmth, and try to minimize their total surface area by tucking in their head and feet and sticking up their feathers. Some species like certain hawks will forgo a solitary lifestyle and form communal winter roosts.
- Some birds, like Chickadees shiver. Birds shiver by activating opposing muscle groups, creating muscle contractions without all of the jiggling typical when humans shiver. This form of shaking is better at retaining the bird’s heat.
- Many species have the ability to keep warm blood circulating near vital organs while allowing extremities to cool down; some can stand on ice with feet at near-freezing temperatures while keeping their body’s core nice and warm.
What can we do to help birds in the winter?
According to the Audubon Society’s Winter Feeding Tips for Birds: One simple way to help birds when the weather outside is frightful is to hang feeders. To attract a diversity of birds, select different feeder designs and a variety of foods. For ideas on what to get for your home, go to: Audubon Guide to Winter Bird-Feeding for tips. The birds benefit from the backyard buffet, and you’ll have a front-row seat to numerous species flocking to your plants and feeders. USE CAUTION, birds come to rely on this as an easy and unlimited food source. If you aren’t going to take the time and spend the money to keep feeders full, it’s best not to start.
Protect winter nesting sites. Just like humans need a warm place to go, bald eagles need shelter to survive harsh winter weather too. Winter can cause even large birds of prey a great deal of stress. The critical point to remember is that bald eagles are very territorial birds, and most breeding pairs return to the same nest site year after year. They may use the same nest annually for up to 35 years. If their nests are disturbed or destroyed, the pair may never build again. The less human caused disturbance the more likely we will have healthy breeding pairs in the spring.
Another thing we can do is not chase birds that are huddled together in large groups. We all know they will get up and fly away if we run at them. Their ability to survive a potential threat costs them a great deal of life sustaining calories.