The landscape is a frozen sheet of white. The wind is biting at my face mercilessly. I can’t help but wonder where the birds are hiding.
In my fluffy big parka and layers I can only stand but little of the this icy chill. What does a little Chickadee do to survive?
They eat and pack away seeds and scraps like fiends when it is warm. When the weather gets colder they need a lot of food energy and body fat to create the heat they will need. I know that they are hidden from the weather in little nooks and cavities and branches of trees.
They have down under their feathers and they fluff things up underneath and on top spread out their feathers as a sort of impenetrable wind-break. They can put one foot up into this protection while standing or can sit down overtop of them to keep them warm or even tuck their head down into a shoulder. They don’t actually need much warmth for their feet as we do because they are covered in scales which, like our hair and nails, are not living tissue. Birds can control the temperature of their feet and legs, constricting flow to prevent heat loss from their extremities.
They also have an adaptation called counter current exchange in which the arteries containing warm blood flowing out to the legs and feet are close to the veins returning cold blood from the extremities. The warm blood heats the cold blood returning to the heart so that their core temperature isn’t reduced. They also shiver like we do to stay warm. Activity increases warmth.
On the coldest -40F day of winter I have seen a Raven out flying. The activity of flying is giving them enough calorie-burning heat that they can expose the undersides of their wings without freezing up like an icicle! Birds are actually called ‘warm-blooded”. There natural temperature is higher than ours to begin with.
Some birds can lower their core temperature as in hibernation for a considerable length of time to conserve their required energy too. Some dive into the snow and use it as an insulating blanket. When it gets warm again they literally just pop out of the snow.
So the Eskimos must have watched the birds and that’s why they make igloos. As cold as snow is, it’s worse without it if you need a cover to survive the elements.