Hummingbirds in Winter
February 12, 2009
The word “torpor” is associated with the Old English O.E. steorfan "to die". Hummingbirds use torpor to survive nights and their bodies’ demands for high-energy food. Torpor is similar to a deep sleep. This Anna’s Hummingbird, Calypte anna (photographed on December 18, 2008 in the midst of a snow storm in Seattle, Washington), stays close to food during the day, and at night seeks shelter so that torpor can be induced. During torpor, the bird lowers its metabolism 95% and its body temperature to an almost-hypothermic level. This allows the bird to survive the wide variety of temperatures at night, both hot and cold.