Birds keeping warm in the winter

Brrrr, it's cold out there! Layer, layer, layer. That's how we survive our runs out to the car, mailbox, or to get firewood. Coats, scarfs, mittens, and boots, oh my!
Sometimes, we spy a bird and wonder, 'how do they keep warm?' But, then we never follow through to find out the answer, and just accept that they do.
Most definitely, winter is harder for them, but they do have some things going for them.
First, their body temperature is warmer than ours at 105 degrees. Secondly, they are wearing layers! Have you ever looked at a bird a thought it looked 'fat'? If a bird actually got fat, it wouldn't be able to fly. Underneath the feathers that we see are light, fluffy down feathers. When we get 'goose bumps', that is a reflex to stimulus that we have very little to no control over. Birds can control it. They can fluff out their feathers. The fluffed out feathers increases the amount of body heat that is trapped under the feathers, and increases the distance of the cold air to their body. The down feathers are such a good insulator, that people have used those feathers in coats, comforters, and pillows for hundreds of years. Today, there are many good alternatives to down.
Birds also have a higher metabolism that helps to keep them warm. But, because they burn energy more in the winter trying to keep warm, they need to eat more. That's part of the reason you may see many more at your bird feeder in the winter.
But, what about their feet? A lot of times you might see them standing on one foot. They will tuck one up to get warm, and then switch. They also might squat down over their feet. The way their circulation works, also helps to keep their feet warmer. The legs, and feet are also covered by hard scales that can tolerate cold and resist frostbite.
Some birds, however, because of the unavailability of their food source, will expend a great deal of energy, and migrate to warmer climates.
Remember to 'like' and 'share' the love of nature!



Sparrows all fluffed up, keeping warm.



Female Cardinal



Down feathers, and a semi-plume feather. Semi-plume feathers are a combination of outside contour feather, with down at the base of it.



Semi-plume feathers.



Down feathers at 21x



Hard, scaly skin of my macaw's foot. Thanks for not biting my iPhone, Sam.