The transparent surfaces of noise barriers along highways or railroad tracks are often dotted with a multitude of silhouettes of black birds, in most cases large birds of prey. That is why these designs play a vital role in wildlife protection.
During a trip on the motorway or train, in the sections where the sound-absorbing panels, everyone has happened to see the “stained glass windows” with curious applied black silhouettes of birds, often so dense that they almost completely occupy the surface. Although they may appear poorly in harmony with the surrounding architecture and natural environment, they play an extremely valuable role in wildlife protection. They are in fact used to prevent birds bump into transparent surfaces, dying instantly or after a long, horrible agony. It is an event that can also occur with the windows of the house and with the windows of large buildings, which represent a real one death trap for birds.
Suffice it to say that according to the study “Bird – building collisions in the United States: Estimates of annual mortality and species vulnerability” conducted by scientists from the Smithsonian Conservation Biology Institute and the US Fish and Wildlife Service, up to a billion birds die every year in the United States from collisions against buildings and other infrastructures with transparent glazing. A huge number, which rises dramatically during the period of migrations. In Italy there are millions of birds that lose their lives in this way, enough to push the FLAG (Italian Bird Protection League) to publish an ad hoc book called “Building with glass and light respecting birds”. It is dedicated to all construction professionals – from designers to architects – to make them aware of the negative impact that the extensive use of glass has onavifauna.
But why do birds crash into clear glass? The reasons are two: i reflexes and the ability to see beyond the glass. A plant positioned behind a glass door, for example, can be mistaken for an excellent roost by a passing bird, which can launch itself against it at full speed, unaware of the barrier in front of it. Even a glass very reflective able to show the surrounding landscape, especially if there are branches and trees, can deceive the keen eyesight of birds. This is why the silhouettes of black birds on the sound-absorbing windows. Often these images show gods birds of prey, from which most other birds keep away; however, these shapes taken individually are not a good deterrent. Practically the entire transparent surface has to be taken up to achieve the desired result.
Video games (still) have a problem with blacks and gays
Obviously the black shapes are a “fallback” solution, since it is possible to use the anti-collision windows, such as those based on materials with low reflective power (opaque and sandblasted glass). Installation can make a difference too, bearing in mind that right angle glazing is much more dangerous to birds than those inclined. As for the houses, it is possible to reduce the risk of impact removing the plants from behind the glass, use lighter curtains e apply mosquito nets on the outside. Some large cities such as Canada are building new buildings with glass that respects birds, while many virtuous companies are replacing old glass with new ones capable of reducing this risk. Also it lights off from dusk to dawn it is very effective in preventing collisions, especially during migration periods. These are all important gestures that have a significant impact on the protection of biodiversity.