National Geographic : 1951 Aug
Freezing the Flight of Hummingbirds By HAROLD E. EDGERTON, R. J. NIEDRACH, AND WALKER VAN RIPER With Illustrations from Photographs by the Authors IF hummingbirds were human, they might well have wondered why lightning was flashing all around them last summer on days of cloudless sky and brilliant desert sun. Flashes several hundred times brighter than Arizona sunlight blinked among the darting birds but disturbed them not a bit. Each of these man-made flashes lasted only 1/5000 of a second. They came from our high-speed flash equipment, developed for what might have been called "Operation Hummingbird." This project had a dual purpose: first, con struction and testing of new lightweight equip ment especially designed for motion-stopping natural-history color photography in the field; second, recording on film the flight of species of hummingbirds new to our cameras. Wings whirring 55 times a second wear a cloak of invisibility. All one can see is a tiny darting ghost in a blur of wings. Hum mingbirds are literally as quick as a flash but not as quick as a modern high-speed flash.* Used with today's color film, it can penetrate the mystery that hides the incredibly rapid movement of hummingbird wings from human eyes. Thus we were able to "freeze" the flight of several species of American hum mingbirds in color for NATIONAL GEOGRAPHIC MAGAZINE readers. Hummers Cooperate with Science These Kodachrome and Ektachrome photo graphs are examples of a special kind of pho tography requiring elaborate apparatus, much hard and patient work, thousands of miles of travel, and the cooperative antics of one of the most interesting and beautiful of birds. Dr. Edgerton had pioneered in this work. He took the first high-speed flash pictures of hummingbirds in black and white in 1928. Picturing the Ruby-throated, only North American variety found east of the Missis sippi, the photographs proved the hum mingbird a most obliging as well as absorbing subject. So courageous that it sometimes tackles hawks, the little creature is so unafraid of man that it can easily be enticed within close-up range of camera and lights. Later, with more powerful lights, Dr. Edger ton made the first flight photographs of hum mingbirds in color and presented the remark able results in the NATIONAL GEOGRAPHIC.t To picture additional species, Dr. Alexander Wetmore, Secretary of the Smithsonian In stitution and Vice-chairman of the National Geographic Society's Research Committee, suggested that we travel west and photograph the dozen or so species commonly found in the Rocky Mountain and other western regions of the United States. Such a task called for a mobile form of high-speed flash photography, sometimes called the "strobe" (for stroboscopic). This brief but amazingly brilliant flash, synchro nized with a camera shutter, had found many important uses. It "stopped" whirling wheels in industrial plants as effectively as it froze hummingbird flight. In World War II, night reconnaissance planes carried extremely power ful sets, weighing more than a ton, for taking photographs behind enemy lines. For natural-history field work, however, the device had to be light in weight and inde pendent of electric power lines. "Suitcase Set" Makes Flash Mobile Working with a grant from the National Geographic Society, Dr. Edgerton and his as sociates designed a battery-operated, remote control flash unit that packed into a 50-pound suitcase. With this "suitcase set," Dr. Edger ton photographed four species of humming birds in the West in 1947. In late May and June of 1950, four of us spent three weeks in the field in Arizona under the joint sponsorship of the National Geo graphic Society and the Denver Museum of Natural History: Dr. Edgerton, professor of electrical measurements at Massachusetts In stitute of Technology; Robert J. Niedrach, Curator of Ornithology, and Walker Van Riper, Curator of Spiders, both of the Denver Museum; and 0. A. Knorr, student ornitholo gist. By that time we had even lighter equip ment. The flash units for each of our three cameras had been engineered down to seven pounds. Expert advisers who contributed to both our projects included Dr. Gilbert Grosvenor; Dr. Alexander Wetmore; Dr. Arthur A. Allen of Cornell University; Henry B. Kane of Mas sachusetts Institute of Technology; Gjon Mill, noted photographer; and the eminent ornithologists Herbert Brandt and Roger Tory Peterson. * See "A New Light Dawns on Bird Photography," by Arthur A. Allen, NATIONAL GEOGRAPHIC MAGA ZINE, June, 1948. t See "Hummingbirds in Action," by Harold E. Edgerton, NATIONAL GEOGRAPHIC MAGAZINE, August, 1947.