A number of birds have the ability to go into a state of hypothermia to survive extremely low temperatures. The bird that is most often mentioned when the subject of hypothermia come up, the ruby-throated hummingbird often comes to mind. You might be surprised to learn that Carolina chickadees also enter a state of hypothermia.

       On cold winter nights, Carolina chickadees like to roost in natural cavities and nesting boxes.  Temperatures inside these cavities are usually higher than those outside the cavity. When it is extremely cold, the chickadees can literally freeze to death with a little help. That is where hypothermia kicks in.

       When a Carolina chickadee goes into a state of hypothermia, its body temperature and heart rates drop dramatically. As a result, the bird may seem lifeless.  The reason why this helps the bird is that in decreases the amount of energy the bird’s body needs to survive. 

       The next morning, as the air temperature rises, the bird’s heart rate and body temperatures increase enough to allow the chickadee to resume its normal activities such as visiting your feeders looking for sunflower seeds.