Why Does A Hummingbird Hum?

And other questions answered about nature's own feathered helicopters.

BY NANCY EILERTSEN
PHOTO BY RICHARD DAY

Hummingbirds are aerodynamic wonders. They have the fastest wing beat in the avian kingdom, clocking in at up to 90 flaps per second during normal activity and 200 flaps per second during courtship. They are also the only bird that has hovering maneuverability—nature's own little helicopters.

Their entire wing is like a tiny propeller that "sculls" (like an oar) from the shoulder, allowing them to fly backwards, sideways and upside down. The wing feathering is what creates the humming sound that gave the bird its name.

Hummingbirds are sugar addicts. Their metabolism is so incredibly fast that they need to refuel about every 10 minutes. Each day they consume 50 percent of their body weight just to maintain their normal weight. Hummingbirds burn from 6,600 to 12,000 calories per day. If a man had the metabolism of a hummingbird, he would have to eat almost 300 pounds of hamburger a day to keep from wasting away.

If you're using a hummingbird feeder to attract these birds, experts recommend mixing four parts water to one part sugar and boiling the mixture for five minutes. They discourage the use of red commercial "nectar" sold in stores, because the additives and/or preservatives are not beneficial to the bird's diet. Don't use honey. It can cause fungal growth, and don't use artificial sweeteners. Most feeders have a little bit of red on them and that will attract the bird. Even a little dab of red nail polish can do the trick. Make sure the feeders are kept clean and change the solution often. A cloudy solution can be hazardous to a hummingbird's health.

The female hummingbird builds the nest and raises the young alone, laying two miniature eggs. Incubation lasts about 16 days. Newly hatched hummingbirds are no bigger than raisins, but grow to adult size in about 1 1/2 weeks. Protein is an essential part of the diet and hummingbirds scarf down tiny insects to meet this requirement. Baby hummingbirds, like all baby wildlife, especially need a high protein diet that mom provides with insects. Baby hummingbirds need to be fed about every 15 minutes.

A full-grown adult weighs only about one-eighth ounce. Its life-span is about nine years.

The popularity of the hummingbird in our society is enormous. Most people are fascinated with these sparkly little jewels of the avian world. In reality, though, a hummingbird's feathers are basically drab. They have a few illusionary tricks, however, that cause their feathers to refract light a certain way and produce a rainbow of colors. That's why various shades of iridescence show up at different angles as the bird hovers from flower to flower.

Nancy Eilertsen is director of the East Valley Wildlife Rehabilitation League in Arizona.

August 2000 11