Many ways for birds to stay warm

The hole shown above was made by a sharp tailed grouse which spent the night under the snow to keep warm. Birds keep warm in many ways. They must forage all day to find enough food to keep their body temperature a few degrees warmer than the air temperature. The thick layer of feathers provides effective insulation, especially when they fluff their feathers which traps the heat. They remain dry when it rains or snows because they coat their bodies and flight feathers with oil secreted by a gland at the upper base of the tail. Some birds have developed additional ways to keep from freezing. For example, Chickadees crowd into a hole in a tree sheltered from the wind and grouse may sleep under the snow. Most birds during extreme cold spells or during a blizzard roost in thick brush or some other shelter for a day or two. Nothing seems to both Ravens. Often they are seen circling around while a frigid wind (especially at -40) sends most wildlife into some kind of shelter.