A hummingbird of subalpine meadows, the Broad-tailed Hummingbird ranges across the south-central Rockies in summer. It possesses a number of physiological and behavioral adaptations to survive cold nights, including the ability to enter torpor, slowing its heart rate and dropping its body temperature.
The Broad-tailed Hummingbird enters torpor, a slowed metabolic state, on cold nights. It maintains a body temperature of about 12.2°C (54°F) when ambient temperatures fall below 10°C (44°F).
In some areas of Broad-tailed Hummingbird breeding habitat, cold air descends into valleys at night, with warmer areas upslope. This phenomenon is called a thermal inversion. The male Broad-tailed Hummingbird, which does not attend the nest, goes upslope at night to conserve heat, reducing the energy costs of thermoregulation by about 15 percent.
Bibliographic Citation: "Broad-tailed Hummingbird (Selasphorus platycercus)." The Cornell Lab of Ornithology.
Citation Link Accessed 24 Jan 2014.
