Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, May 13, 1990 TAG: 9005100415
SECTION: EXTRA PAGE: E-5 EDITION: METRO
SOURCE: PATRICIA C. HELD
DATELINE: LENGTH: Medium
But while this description might make these creatures sound mythical, hummingbirds can be found right in our own gardens, enjoying the assortment of colorful blossoms that our area has to offer.
West of the Mississippi River, there are many species of hummingbird, but in Virginia there is only one, the ruby-throat.
Named for the male's brilliantly colored throat, the birds are metallic green above and white below. Actually, the feathers are not colored at all. They are barbed and channeled to refract light like a prism capturing the sunlight.
The tiniest of birds, hummingbirds are lighter than a penny. Yet they have remarkable powers of flight. They are able to beat their wings 55 times per second and navigate more like a helicopter than a bird. Hummingbirds can hover in midair, go up and down, forwards and backwards and can travel at 50 mph - all the while making a loud buzzing sound. No wonder they are often mistaken for insects.
Ruby-throats are well suited to life as stunt pilots. Although they have very weak feet and are clumsy on the ground, they have well developed muscles and a large heart. Their breastbone muscles are four times as large as that of a pigeon and their heart makes up a quarter of their body weight. Constantly in motion, perch for only short amounts of time to survey their surroundings.
During migration, their powers of flight are tested to the extreme. Ruby-throats travel south each autumn. One day the feeder may be filled with hummingbirds and the next day they are gone. To prepare for their journey they eat tremendous quantities of food. Their bodies act as tanks to store extra fuel for the trip.
On their flight, hummingbirds stop for refueling in Florida, Then take a 500-mile nonstop flight across the Gulf of Mexico to Central America. During this extended trip, the little birds lose up to half of their body weight.
In the spring, hummingbirds move North to keep pace with the blooming of their favorite flowers. By mid-April they have reached Virginia again and become a common sight at the feeders.
Hummingbirds are equipped with the perfect instruments to obtain nectar. They have needle-like beaks and long tongues that can pump out nectar from the bottom of long tubular blossoms.
Because of their high metabolic rate hummingbirds burn up energy very quickly and must eat every fifteen minutes. They could not possibly eat enough food to sustain them through a full night, so they have evolved a unique method of coping. They find a perch and go into a state of turbidity, a kind of suspended animation. During nighttime hours, their body temperature drops to the level of the surrounding air temperature. Their reactions and breathing rates slow down as if they were in hibernation.
A hummingbird's courtship is a fanciful affair. Unlike birds that use melodious singing to attract their mates, male hummingbirds do a dance. Once a male has spotted a likely mate he rises into the sky and drops to one side of the female, then rises on the other side in a pendulum arc. With each dip he buzzes loudly. If this elaborate dance does not attract her, his brilliant feathers will.
Once mating takes place the male hummingbird disappears. He takes absolutely no part in the nesting activity and is even suspected of polygamy. The female bird could care less, She is far to busy looking for a suitable nest site close to a food supply.
Their nests are unlike those of most birds. First of all, they are tiny, only the size of a quarter. Hummingbirds build their nests from the scales of opening tree buds and the wooly parts of mullein, cover it with lichens and line it with dandelion fluff and thistle down. Saddled in a branch in a forest clearing, the nests are secured with spiders' silk.
Her nest complete, the female hummingbird lays white, pea-size eggs. After sixteen days of incubation, the young are born totally blind and featherless and from dawn to dusk, the mother bird feeds her babies nectar, spiders and small insects at four minute intervals. Within fifteen days the young have outgrown the nest, but the mother continues to feed them insects as they learn to sip nectar on their own.
Hummingbirds are attracted to colorful tubular flowers. Petunias, salvia, columbine, trumpet vine, morning glories and honeysuckle all help attract these birds to our gardens. Hummingbird feeders, available at garden supply stores, should be filled with colored sugar water made from one part sugar and four parts water.
Patricia Held will respond to readers' questions on the plant and animal wildlife in the region. Mail inquiries to: Patricia C. Held, P.O. Box 65, Goode, Va. 24556.
by CNB