Air traffic and bird migration: peaceful coexistence in the sky: when ornithologists inform the air force

June 11, 2022

Israeli Air Force jets are grounded when storks, cranes or lesser spotted eagles pass through the country on their way to their winter quarters in Africa. Since the “Air Force Migratory Center” has existed, there have been hardly any collisions. By Thomas Krumenacker

Every year in autumn and early spring, Israeli nature lovers receive electronic mail from an unusual place. “The Air Force’s migratory bird center has resumed its work,” the Air Force e-mailed to the birdwatchers’ community, which is also growing in Israel. “We would be pleased if you would keep us informed of any concentrations of birds,” says the circular from the Air Force Coordination Center, which is manned day and night at Ben Gurion International Airport near Tel Aviv.

Here, Air Force soldiers sit in front of a battery of screens and phones, gathering real-time information on what’s happening in Israel with feathers. They get data from various radar stations, from the towers of the individual bases, from the biologists stationed at every military airport – and of course from bird watchers. If a flock of lesser spotted eagles, pelicans or white storks crosses the vicinity of an airport, the aircraft are prohibited from taking off until the birds are out of range. A win-win situation: the birds remain unmolested, and a hazard to aviation and passengers is averted.

This cooperation between flight safety and nature lovers has a solid reason. The small country – Israel is smaller than Mecklenburg-Western Pomerania – is one of the most important hubs for bird migration worldwide. It forms a kind of land bridge at the interface of the continents of Europe, Asia and Africa.

Particularly heavy and large birds such as the lesser spotted eagle avoid flying over larger open water areas on their journey of many thousands of kilometers. They cannot land there if they are exhausted, but most importantly, no thermals form over the cold water. These warm upward winds, which are created over land by the sun’s rays, help the birds to be carried in gliding flight in an energy-saving manner. The heavy aircraft can thus reduce strenuous active flight to a minimum.

However, the geographical location also means that a particularly large number of the large birds that are problematic for aviation are concentrated in Israel: in addition to often more than 100,000 lesser spotted eagles, there are 360,000 honey buzzards, 50,000 white pelicans and 600,000 white storks within a few weeks of the year. In total, around 500 million birds migrate across the Middle East every migration season.

The merit of Yossi Leshem

It was the ornithologist Yossi Leshem who largely defused the human-bird problem. He observed bird migration for hundreds of hours and presented his dissertation in 1984: a detailed overview with the exact course of the various bird migration routes over Israel and precise information on which bird species flies which route at what time. From this, the aviation authorities distilled their own map, which was given the title “List of birdplagued zones”. After some changes, the flight bans in the “bird plagued zones” came into force in 1985. With modifications, they are still valid today.

During the main passage of the large birds, the affected airspace is then briefly closed until radar and bird watchers give the all-clear. The concept, for which Leshem has received many international awards, still works today. In the ten years prior to the completion of his studies, the Air Force recorded an average of one fatal accident every two years and 35 other incidents each year, each costing more than a million dollars. In the three and a half decades since Leshem’s concept came into force, the number of collisions with major property damage has been reduced by 76 percent, according to official figures; the state saved $1.3 billion. More importantly, there has only been one fatal incident since then.