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Tracking the 530 known species of birds migrating to and through Israel in the spring and autumn of every year paid off, literally, for the Israel Air Force, which shares the same air space. Through the efforts of a local ornithologist commissioned by the IAF, the flight patterns of these birds are thoroughly explored, meticulously recorded — and avidly avoided. As a result, the IAF estimates that bird strikes have been reduced significantly since 1984 when the study was first commissioned, saving Israel $450 million.

In the last twenty-five years, the IAF has suffered 3,092 air collisions with birds for an average of 258 bird strikes per year. Eight aircraft were lost and three pilots were killed. The IAF determined to learn more about the birds when more aircraft were lost to bird strikes than to the combined might of Israel’s enemies. After every bird strike, a bird specialist was called in to examine the feathered remains. The specialist soon compiled an encyclopedia of feathers to show that migrating birds were the culprits. IAF commanders then commissioned the Society for the Preservation of Nature in Israel to study the habits of these migratory birds to learn a peaceful co-existence and to reduce air collisions. As head of the SPNI, Dr. Yossi Leshem undertook the study.

His findings? Israel is a bottleneck of migrating pelicans, storks, seagulls, cranes, swifts, finches, wagtails, warblers, starlings — some coming from as far away as Siberia, Germany, and Afghanistan. Almost 500,000 storks pass over Israel twice a year on their annual migration. They come from Poland, Russia, and the Czech Republic on their way to Kenya. Some fly as far south as South Africa. Some, like seagulls, stay and feast off landfills near Ben-Gurion Internationl Airport. (Civilian aircraft lost to bird strikes present a whole other count.) Altogether, 500 million fowl pass through Israel in one year. This exodus is second only to that over Panama in Central America.

Among the more surprising discoveries was the number of lesser-known eagles spotted, 140,000 in one migratory season. They arrive within the same four to five days each year, generally migrating when the length of the day changes. The pelicans are the largest in size (three-meter wingspan) and the greatest in number to migrate Israeli skies. Seventy thousand pass through in one year, flying in orderly formations. Unlike the more direct eagles, the pelicans take almost two months to pass through. Buzzards, on the other hand, never drop below 2,000 feet or soar above 5,000 feet. Altogether, the numbers of birds migrating through Israel were four times greater than previously thought.

The birds leave their home perches in the fall before the cold and snow of winter deplete their food sources. On their journey for survival, they search for thermals — warm air moving upwards — to hitch a ride along the way and conserve their energy. Conditions for thermal gliding are excellent in Israel — over the very same strip of land used by Israeli pilots for training.

The IAF couldn’t halt training during these seasonal migrations. While researchers studied the birds in flight, IAF instructors on the ground gave pilots a lesson in Newton’s Law of Action and Reaction. A bird hits the aircraft with the same force as the aircraft hits the bird. In other words, a bird striking a fighter traveling 900 kilometers per hour produces twenty-five tons (25,000 kg) of impact. Thus, even a small bird penetrates a fast flying jet like a bullet. Once the physics is described, the pilots watch an Aircraft Industries video of a bird striking a cockpit mockup. A camera loaded in the pilot’s seat shows the impact to the cockpit and to the pilot. The pilots see how they can easily be killed by any bird. Even if a pilot survives the impact, he may be briefly knocked unconscious by the impact, regaining consciousness only to find his visor plastered with bird remains.

With so many birds competing for the same airways, pilots had to learn to fly with the birds, instead of into the birds. Data gathered from bird watchers on ground, radar, and glider aircraft were put into one instructional and reliable source. Flight training was coordinated not to clash with the birds. Bird paths were analyzed and plotted so IAF pilots would not cross into them. Maps put up in squadron rooms charted the altitudes and migration schedules of birds so that pilots could plot alternate paths. For example, pilots can fly below or above the buzzards. As a result of these combined efforts, the IAF reduced bird collisions by eighty-eight percent and saved millions of dollars along the way.

Leshem is now taking bird strike data to a new level of awareness, the world. He is creating a global database at the International Center for Study of Migration at Letrun, Israel, to track bird movements and bird strikes in military and civilian flight. The data will be used to evaluate the rate and cost of global bird strikes and to develop a regional model of bird movement based on a Geographic Information System. The model is being developed in cooperation with the US Air Force Academy in Colorado Springs, Colorado. Contributors to the system will have access to the database for their needs. EMC2, the leading developers of data storage systems, and Lockheed Martin are cooperating in this project.

Article by Mary Lou Vocale

Mary Lou Vocale is the editorial assistant for Code One.