it survived

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This chickadee survived the winter. And it was a particularly cold and deary one here in the Tennessee Valley.

"Chickadees have a body temperature of 107° F and because many members of the family do not migrate, northerly breeders risk freezing to death during winter. In contrast to human babies and bears, birds have no brown (heat-generating) fat. So, somewhat like adult humans, their only method of generating heat is to burn fat, which they do by using their muscles. When their body temperature starts to drop below 70° F, chickadees must generate heat themselves, and to do this they need to expend energy. We can jump up and down, but what can birds do? The answer is that chickadees shake in their sleep during the winter, shivering to keep their bodies warm.

Ninety-eight percent of the energy of a small bird is used for heat regulation and for basic metabolism, leaving 2 percent for foraging. Shouldn't the bird keep still and save that 2 percent for heating? The scenario is horrifying: On a cold winter's day two million chickadees out there would have to choose between freezing or starving to death.

It is not as bad as that. It isn't actually possible for a bird to save energy by being inactive instead of foraging, because its alternative would be to sit still and shiver to keep warm, thereby expending the same amount of energy. In contrast, using muscle power when foraging generates 'bonus' heat."

- From the wonderful book: "Between the Wingtips: The Secret Life of Birds" by Östling and Ullman available in the Ijams gift shop

- Photo taken at Ijams Nature Center

-Thanks Karen Sue


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