Reduced Metabolism: When resting, hummingbirds significantly lower their metabolic rate. This helps conserve energy since their normal state requires high energy expenditure.
Torpid State: To conserve energy, hummingbirds often enter a state called torpor. During torpor, their body temperature drops drastically, and their heart rate slows down.
Decreased Heart Rate: In torpor, a hummingbird's heart rate can drop from over 1,000 beats per minute to as low as 50 beats per minute, minimizing energy use.
Lowered Body Temperature: The body temperature of a resting hummingbird can fall close to the temperature of their environment, sometimes dropping to 10°C (50°F) or lower.
Reduced Respiration: Breathing rates slow significantly during rest. A hummingbird's respiratory rate can drop from 250 breaths per minute to just a few breaths per minute in torpor.
Less Activity: While resting, hummingbirds are almost completely inactive. They remain motionless and avoid activities that could use up energy.
Recovery Period: After periods of torpor, hummingbirds need time to warm up and regain their normal metabolic functions. This process can take several hours and requires energy intake from feeding.