What happens when the solution to a serious problem has a deadly result? Anyone driving on one of Israel’s many main highways has seen the high acoustic barriers constructed along the way to reduce or block traffic noise suffered by communities near the heavily trafficked roadways.
Many of these acoustic walls are transparent, which makes them especially lethal to birds. For birds in flight, see-through acoustic walls are a direct continuation of their flight path, especially if trees and shrubs are located beyond the barriers.
Though a very small country, Israel is a major bird migration corridor. It is also what’s known as a global biodiversity hot spot, which means there are a lot of birds – both local and “tourists” – on their way north or south, depending on the season. Half a billion migrating birds, more than 230 species, fly in Israeli airspace on annual migrations between Europe, western Asia, and Africa. The high intensity months are March and April, as well as the end of summer, when the inexperienced fledglings take flight.
A recent study carried out by teams from the Ayalon Highways Company, the Israel Nature and Parks Authority, and the Society for the Protection of Nature in Israel revealed that hundreds of thousands of birds in Israel die every year because of colliding into transparent acoustic walls, as well as smashing into windows in high-rise buildings.
A new project launched by Israel’s environmental organizations, the highway authorities, and the Transportation Ministry deals with this lethal threat to birds, with the aim of saving hundreds of thousands of birds each year.
ISRAEL IS one of the most crowded countries in the world. “That means there are too many people in a small area, too many cars, too many roads, too much noise pollution because so many roads are adjacent to residential areas,” says Yoav Perlman, director of the Israel Ornithological Center, a division of the Society for the Protection of Nature in Israel (SPNI).
In order to deal with the issue of noise pollution, government regulations require that highway companies erect acoustic barriers where major roads will generate noise above a certain level and are adjacent to populated areas. Every year, more and more barriers are constructed along the highways.
As in most other countries, roads in Israel are constructed and paved, made wider and straighter, with little concern for wildlife. “Because of Israel’s rapid development and expansion, the interaction between built-up area, highways, and open spaces is getting tighter and tighter,” Perlman explains. “Dangerous interactions take place when there are acoustic walls along highways that intersect open spaces on one side and towns with open areas on the other side of the barrier.”
The SPNI, together with the Israel Nature and Parks Authority, recently published their study on the number of birds that die as a result of hitting see-through acoustic barriers. They used sniffer dogs to locate the remains of dead birds carried off by predators. “With the data collected in the study, we made a very rough estimate of how many birds are killed from acoustic barriers. It’s in the range of hundreds of thousands of birds every year,” Perlman states.
A critical part of the research project was carried out by the Israel Nature and Parks Authority’s Science Division on acoustic barriers near Atlit, the coastal region just south of Haifa. “These barriers are particularly problematic because they are close to salt pools, which attract many migratory birds,” says Dotan Rotem, an open spaces ecologist at the authority. Every year, more and more barriers are added. The survey’s results showed that for every 50,000 meters of transparent walls, 114,000 birds are killed annually.
In some places, stickers of birds of prey have been affixed to the barriers, but these have proven only partly effective, adds Rotem, “since most of the walls are transparent. This especially affects doves and pigeons which fly at low levels and crash into walls and windows. We tend to think about migrating birds, but most of the deaths are of local birds.”
Dr. Ariela Rosenzweig, a veterinarian who treats injured wild animals at the Israeli Wildlife Hospital in the Ramat Gan Safari Park, has been witness for years to the high number of birds killed or seriously injured by smashing into the barriers. Most can’t be saved.
A key member of the joint team working on the project to reduce the impact of the clear acoustic walls on Israel’s bird population, Rosenzweig notes that “there is growing awareness about this problem in the rest of the world, but here we’re just starting, even though it’s been a well-known problem since the 1970s. The techniques to prevent this are known, and the costs aren’t high.”
WINDOWS IN high-rise buildings can be death traps for birds as well. Anyone who lives or works in a high-rise building of up to 20 stories is familiar with birds colliding into the windows. Birds collide with glass windows because they see reflections of the landscape or clouds in the glass. The reflections are a lethal illusion of clear airspace.
Windows that are as high as tree tops are the most problematic for bird crashes, explains Rosenzweig. Sixty meters from the ground is the highest level that needs to be protected. There are various methods of designing windows to reduce reflection, she says. “These can be quite beautiful; you just have to persuade architects to be open to new things. This is happening already around the world, but in Israel people are not aware of this issue. But there are creative methods to keep birds from crashing into windows.”
What is the solution?
A pilot study by the Ayalon Highways company showed that by using barriers that are milky or tinted, birds will avoid them. Another method is by adding stickers, or manufacturing walls with dots or thin vertical lines.
The Transportation Ministry has now begun installing bird-friendly acoustic walls along the Ayalon Highway (Route 20) and the Coastal Highway (Route 2), in cooperation with various municipalities. (In the stretch of the coastal highway near the Wingate Sports campus, the solution is a colorful display of what’s on the other side.)
“The phenomenon of dead birds can be avoided if stickers are applied during production; the costs are negligible,” says SPNI’s Perlman. “There are still thousands of kilometers waiting to be dealt with. This has been done all over the world, but here the migratory patterns are particular critical.”
While the major local manufacturers of the plastic barriers have agreed to adopt the recommendations of the plan to produce bird-friendly walls, it may take a few years before they are ready. And to date, the Transportation Ministry has not yet green lit the project that would provide the needed funding.
“Every day, even more barriers are erected and thus more birds crash and die,” says Perlman. “The most frustrating thing is that this problem is totally and easily solvable; it just needs the willingness of the authorities to make the move.” ■