Hummingbirds sleep on their favorite perching spots, such as on a feeder or on a high, secure location with enough visibility. Hummingbird sleep is notable because it is actually a form of hibernation called torpor, where the body expends about one-fifteenth of the energy it normally uses.
The body temperature of the hummingbird drops significantly during torpor, while the heart beats approximately 50 beats per minute. Breathing also slows and can even appear nonexistent to an observer. Hummingbirds in torpor can easily be mistaken for dead, as they also often sleep upside-down. Due to the extreme conditions of torpor, hummingbirds that awaken require about an hour to resume daily activities.