The helicopter with feathers
By Dr. Robert A. Hedeen, Naturalist
My daughter-in-law, Norma, recently gave me a hummingbird feeder with a supply of synthetic nectar, and I dutifully hung it from a limb in the wooded area behind my house. I had no idea if this lure would attract hummingbirds, but the other day I was pleasantly surprised when it did. I was sitting on the deck reading in the afternoon when I became aware of a deep, sustained, droning, humming sound that was not unpleasant to my ears. Looking around to determine the source of the buzzing, I saw a female ruby-throated hummingbird hovering under the feeder. Fortunately, the tiny creature was oblivious to my presence, and I was able to observe it in action from close range for about five minutes.
The hum of the bird was caused by the rapid vibration of its wings and varied in intensity as it hovered around the feeder extracting the sweet sugar compound with its elongated beak. The wing motion was so rapid it was invisible to the eye (I read somewhere that a photographer who was a physics professor at M.I.T. once used an electronic flash exposure of 1/10,00th of a second to freeze the action of both wings of a hummer in flight).
The extraordinary flight powers of the hummingbird are correlated with enormously developed breast muscles and a special arrangement of the bones in the wings. The entire shoulder can be rotated forming a variable pitch propeller, much like a helicopter, that can push air in almost any direction on both forward and backward strokes. Not only can a hummer hover by beating its wings on a horizontal plane, it can rotate the wings even further so backward flight is possible. The hummer is the only bird that can fly backward.
The expenditure of so much energy by the wing muscles requires the bird to rest frequently. These avian dynamos use so much energy which they must ingest their weight in calorie-rich carbohydrates several times each day. Small insects found inside the corolla of a flower supplement the primarily carbohydrate diet.
Hummingbirds are the smallest birds in the world and are real all-Americans, being only found from Patagonia to Canada. There are several hundred species of hummers, but most of them are tropical in distribution. About a dozen species venture north, and most of them are observed in the western United States. Only a single species is routinely found east of the Mississippi River, the ruby-throated hummingbird. This bird derives its name from the glittery gorget worn by the male and displayed at its fullest during the mating season. The female lacks the ruby throat and has white spots on her blunt tail. The male has a forked tail.
All hummingbirds are small, with only one being more than five inches in length, including the beak and tail. The smallest is the bee hummer of Cuba. This insect-sized bird is only 1-1/2 inches in length, including the beak and the tail, and holds the title of the worlds smallest bird.
The nest of the ruby-throated hummer is a tiny lichen-covered cup that is down-lined and fastened to a branch that is constructed three to 30 feet above the ground. Two small eggs are laid and incubate in about two weeks. The young are fed by the vigorous pumping of liquid food from the stomach of an adult.
When fall arrives, hummingbirds head for warmer climes south of the border. By properly metabolizing about 2 grams of fat making up a total body weight of about 4 and 1/2 grams, the bird can fly approximately 650 miles without refueling. The ruby-throated hummer frequently makes its nonstop migration from the southeastern states across the Gulf to Mexico, Central, and South America.
In addition to providing us with the pleasure of watching the outstanding aerodynamic skills of one of the most remarkable creatures in the animal kingdom, they are beneficial to mankind as a major pollinator of many species of plants.
It is suggested that anyone interested in natural history get a hummingbird feeder and get a ringside seat to witness a scenario of the ever-unfolding drama of the natural world.
Dr. Robert A. Hedeen is a former resident of Marylands eastern shore and resided in the Chicago area from 1960-1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.