From “Mute Dancers: How to Watch a Hummingbird”
photo by Anna Katrina
When the dawn breaks on the fuschia and columbine, hummingbirds must jump-start their hearts and fire up their flight muscles to raise their body temperature for another all-or-nothing day. That demands a colossal effort, which some can’t manage. So a lot of hummingbirds die in their sleep.
But most do bestir themselves. This is why, in American Indian myths and legends, hummingbirds are often depicted as resurrection birds, which seem to die and be reborn on another day or in another season. The Aztec god of war was named Huitzilopochitl, a compound word meaning “shining one with weapon like cactus thorn” and “sorcerer that spits fire”. Aztec warriors fought, knowing that if they fell in battle they would be reincarnated into glittery, thuglike hummingbirds. The male birds were lionized for their ferocity in battle. And their feathers flashed in the sun like jewel-encrusted shields. Aztec rulers donned ceremonial robes of hummingbird feathers. As they walked, colors danced across their shoulders and bathed them in a supernatural light show.
My encounters with hummingbirds have been altogether more benign. Whenever I’ve walked through the South American rainforests, with my hair braided and secured by a waterproof red ribbon, hummingbirds have assumed my ribbon to be a succulent flower and have probed my hair repeatedly, searching for nectar. The touch was as delicate as a sweat bee’s but the purring by my ear made me twitch. In Portugese, the word for Hummingbird means “Flower Kisser”.
Now that summer has come at last, lucky days are to be spent watching the antics of hummingbirds. The best way to behold them is to stand with the light behind you, so the bird faces the sun. Most of the trembling colors aren’t true pigments, but the result of light staggering through clear cells that act as prisms. Hummingbirds are iridescent for the same reason soap bubbles are. Each feather contains tiny air bubbles separated by by dark spaces. Light bounces off the air bubbles at different angles and that make blazing colors seem to swarm and leap. All is vanity in the end.
Diane Ackerman
Zoe Ann Hinds said,
September 4, 2008 at 6:27 am
Yes, hummingbirds do sleep. They do so at night by entering into a state known as torpor, which is a state similar to hibernation. Hummingbirds must enter this state to ensure that the birds won’t actually starve to death before down. Torpor is a type of deep sleep where an animal lowers its hart and metabolic rate. In a state of torpor the hummingbird lowers its metabolic rate by as much as 95%. A torpid hummingbird consumes up to 50 times less energy than when awake. The lowered metabolic rate also causes a cooled body temperature. A hummingbird’s night time body temperature is maintained at a level which is barely sufficient to maintain life. This level is known as their set point and it is far below the normal daytime body temperature of 104°F or 40°C known for other birds of similar size.
There are many reasons why the hummingbird must enter into a state of torpor. Hummingbirds are among the smallest of all warm-blooded animals, and they also lack the insulating downy feathers that are typical for many other bird species. Due to their small body size and lack of insulation, hummingbirds rapidly lose body heat to their surroundings. Even sleeping hummingbirds have huge metabolic demands that must be met in order for them to simply survive the night when they cannot forage. By entering into a state of torpor, a hummingbird is able to save enough energy to survive cold nights by lowering their internal thermostat.
There are several types of torpor. The various types of torpor are classified mostly by duration and season. If the state of torpor takes place over a long period of time during the winter, it is known as hibernation. However, unlike hibernation, hummingbird torpor can occur on any night of the year so it is referred to as daily torpor or noctivation. Tropical hummingbird species also have rigid metabolic demands and even they rely on daily torpor to conserve energy.
The sleep of torpid hummingbirds is a sleep that is as deep as death. According to the book, American Ornithology, written by Alexander Wilson in 1832, torpor is described as follows: “No motion of the lungs could be perceived … the eyes were shut, and, when touched by the finger, [the bird] gave no signs of life or motion.”
It takes approximately 20 minutes for a hummingbird to awaken from a state of torpor. When awakening, the hummingbird’s heart and breathing rates increase and they vibrate their wing muscles. The bird’s blood supply will be warmed by heat being generated by their vibrating muscles or from shivering. Shivering helps to warm the hummingbird’s body temperature by several degrees each minute and the bird awakens with enough energy reserves to see him through to his first feeding of the morning. Hummingbirds reliably awaken from torpor one or two hours before dawn without any known cues from the environment. It appears that the bird’s internal circadian clock is responsible for signaling when it is time to awaken from the state of torpor.
Hummingbirds are not the only birds known to enter into a state of torpor. Other birds that are known to enter into a state of torpor include swallows and swifts. Scientists think that most small birds living in cold regions, such as chickadees, rely on torpor to survive long cold nights. Rodents, bats and other small mammals typically show some form of regulated hypothermia during cold weather, and these animals can only rely upon daily torpor during the winter months when they are not breeding. For hummingbirds, noctivation is possible on any night of the year. It is the hummingbird’s ability to enter into a state of torpor that will literally prevent it from starving to death before dawn.
If you would like much more information about hummingbirds, please click the links below. The sites contain many articles about hummingbirds, video clips about hummingbirds, an informative tips booklet on hummingbirds, and much more.
Click Here To Visit About Hummingbirds
Hummingbirds For Mom