I am sure many of us in this burst of heavy winter weather have been thankful when running from the car or between buildings to reach the sanctuary of a warm home or office.
I looked out upon the feeders I have around my house and saw them covered with birds. Especially during the deep cold and freezing temperatures, I try to keep the feeders stocked. It is expensive to fill them all the time, but when the temperatures drop, I can better justify the seed. It is amazing to see the little American goldfinches, chickadees and even the juncos and wonder how they stay warm. Even a chipmunk ventured out to see what the thunder was going on. Now that was an unusual sight.
Warm-blooded animals like mammals and birds are homeothermic, meaning they control their own body temperature. How? Through evolution, adaptation, and quite simply by the incredible way in which they were made.
The main thing birds have going for them in winter is their down, a specialized feather found underneath all of the other feathers. It is soft and fluffy. Many of us have had down coats, vests and even comforters – so good at trapping warmth. Don’t worry, down found in coats and vests doesn’t come from songbirds. It comes from chickens, ducks and geese.
Have you ever seen a bird’s foot up close – maybe a chicken’s? It’s covered with specialized scales that help reduce heat loss. Birds also can constricting blood flow to their extremities, reducing heat loss.
Here is how even the smallest bird can get through a freezing winter: They build up fat stores in the fall, when food supplies are the most plentiful. Not only do the fat reserves provide insulation and extra energy for body heat, the fat is used throughout the winter when food is more scarce.
Birds have made behavioral adaptations, too. You may have seen birds all fluffed up on a cold winter day as it is snowing and blowing. Fluffing their feathers creates air pockets, further trapping warm air against their body.
You may have noticed a bird standing on one leg with the other tucked up against his body. Or, another bird with his bill tucked down against his shoulder. Imagine what you do when you have only one glove and the temperatures drop. You shift the glove between one hand and the other.
Roosting is a common practice among birds trying to stay warm and if the roosting site is not properly chosen, it can be a killer. Bluebirds are especially prone to this one. Many bluebirds will fly to southern Missouri and Kansas, or even a bit further south to escape the cold, and if temperatures drop they will often roost. They choose a deep cavity and all pile in.
Page 2 of 2 - Anywhere from two to 10 birds can be found in one roosting site. This can be a bluebird box, for example. If the box is not made of the recommended one-inch-thick lumber, they could freeze. I witnessed this a few times while I was a nature center manager. It breaks your heart.
You may have witnessed a bird shivering. Yes, they are cold, but they are also staying warm. Shivering will raise their metabolic rate (same as it does for you), but it will also burn more energy. This is not the best solution, but it works in the short term. Again, get out the birdseed and water. Birds can make water from snow if they have to, but that takes precious body energy.
During this snowy weather, I hope you have been able to spread some seed, get a mug of hot chocolate, and watch the birds. Tallyho!
Reach Lynn Youngblood at TheGreenSpace@sbcglobal.net.