Fall 2010

It sure has been very c-c-c-c-cold this winter! I hope y’all have been keeping warm! Well, of course, you have. It’s easy for people to keep warm. You just put on more clothes or turn up the heat in your house. My friends and I don’t have that capability. Have you ever wondered how we (birds) stay warm when it gets so cold? Well, I’ll share our secret with you.

We have several adaptations that help us stay warm. Feathers are one of the most important adaptations. We have different kinds of feathers. Most of us have soft, fluffy, down feathers, which are next to our body.  This is like having a down jacket. When we are cold, we fluff up our feathers, putting a layer of air between them and trapping the heat next to our bodies. Not only does this help insulate my body against the cold temperatures, but it also makes me look bigger, too!

For most of my friends and me, our legs and feet are covered in special scales, which keeps heat loss very low. Near my legs in my body the arteries that carry my blood from my heart to the other parts of my body are right next to my veins which contains blood returning back to the heart. Usually, the arteries and veins are not very close to each other. Before the blood reaches the legs and feet, most of the heat has transferred to the blood in the veins, warming it up before it gets to the heart. There is enough heat in the arterial blood to keep the feet and legs from freezing. This is not a trick that I control because it works automatically, just like your blood flow works automatically for you. Some of my northern bird friends have feathers on their legs to help keep them warm during those cold, northern winters.

We eat a lot of food in the fall to build up a layer of body fat to keep us warm and give us energy. This high energy food not only provides that layer of fat to insulate us form cold, but it also gives us the energy to shiver- quickly shaking our muscles. You shiver when you are cold, too. Shivering raises our body temperatures, but this is a short-term trick against the cold weather.

I could have all the adaptations in the world, but if I don’t use them, they won’t help me. We have a few other tricks to keep us warm. Some birds will roost together in large numbers. My chickadee, titmouse, and nuthatch friends do this. They will crowd close together in tree cavities, roost boxes or in evergreen trees and shrubs. They share body heat by snuggling close together in those small areas.  I do not like to be that close to others. Birds like me will find shelter near areas that have residual heat (places that are still warm from the day). We might sleep next to a tree trunk, a building, or something dark in color. We also like to find evergreen shrubs and trees. The year-round leaves keep the wind, rain and snow away from us.  We might also stay in a roosting box or birdhouses to get out form the weather.

During the day, my friends and I may sunbathe in winter. We may sit in sunlight or slightly spread our wings and tails to allow the sun to heat up our feathers and skin as much as possible. When we sleep, we may tuck our beaks under our wings. This means we are breathing the warm insulated air from around our bodies instead of the cold, outside air.

One last method some birds use to keep warm is called tupor. These birds slow down their body functions to conserve energy at night, therefore, requiring less energy (calories) to maintain proper heat. Body temperatures are generally lowered a few degrees.  It is not the same as hibernations because tupor is just overnight, hibernations lasts from many weeks or months. Hummingbirds, chickadees, and swifts regularly use tupor to survive cold temperatures. This can also be very dangerous because the reduced body functions also means slower reaction times to escape predators.

During normal winters, know that my friends and I are OK, but during very frigid winters, we may need a little help from you. Planting evergreen trees and shrubs, creates a sheltered place for us to get away from the wind, rain and snow. Brush piles can help protect us, too. My winter friend, the Fox Sparrow, likes brush piles. Keeping your feeders filled with bird food that is high in fat and calories (suet, black oil sunflower seeds) give us the energy we need. Providing water for us to drink, by breaking the ice in birdbaths or pouring hot water on the ice, will give us a better chance to survive than waiting for the ice to melt. Many of you helped my friends and me this winter and I want to thank you for your extra help!