The Flight of the Hummingbird
A route of evanescence
With a revolving wheel
A resonance of emerald,
A rush of cochineal
With these words, the poet Emily Dickinson summed up the fleeting magic of the hummingbird.
Hummingbirds are the only vertebrates capable of hovering in place. In addition to flying forwards, they can also fly backward and upside down! They are tiny: the smallest bee hummingbird of Cuba weighs less than 2 grams, less than a penny! Add to this their speed- they can clock up to 45 mph, and stamina- they can fly 18 straight hours, and you may appreciate their unusual metabolism. In fact, they have the highest metabolic rate of any warm blooded animal.
With a heart beat of 1,200/min and wing beat of 200/sec during flight, hummingbirds generate a tremendous amount of heat. Because their muscles are only ~10% efficient, much of the energy they consume is released as heat. But their thick plumage of feathers keeps in the heat: useful when the bird wants to conserve body heat, but a problem during flight.
Using infrared thermal photography, scientists have found that hummingbirds (and probably most birds) lose body heat from three areas seen as bright white spots in the gif below: the region around the eyes, at the shoulder where the wings meet the body, and the feet, which they can dangle downward to dissipate even more heat.