Glass facades: The quieter killers of our feathered friends. At the same time, killing can be reduced


In addition to April Fools’ Day, there is another important holiday on April 1 – International Bird Day. It will remind us how significantly human civilization affects the life of birds. Birds mistake glass facades for a safe oasis of greenery, and a collision with them is often fatal for them.

Few people know that glass facades, which are most often found on office buildings in larger cities, are one of the biggest dangers for birds. In the Czech Republic alone, approximately one million birds die each year as a result of hitting glass, and worldwide this number is estimated at up to one billion.

Fortunately, there are now specially developed glasses that can protect them from impact. Michal Široký, a glazing expert from the Saint-Gobain Building Glass company, explains how they work.

Danger to birds

Birds move at great speed – tiny songbirds fly at speeds of 30 kilometers per hour and pigeons, for example, at speeds of up to 70 kilometers per hour – and unlike humans, their eyes are located on the sides of their heads.

Therefore, they see the sharpest to the sides and do not pay so much attention to the space in front of them. They are also unable to distinguish reality from mirror reflection. They often confuse the mirror surface with safe greenery. Because of this, however, we do not have to get rid of glass facades on houses, which have their indisputable advantages. Just choose bird-safe glass.

One silhouette doesn’t work

Source: Youtube

Reflections also do damage

Glass facades pose a danger to birds for two partially contradictory reasons. “If the glass is too transparent, the birds are not aware of its presence and believe that they can fly freely through the space. However, opaque windows reflecting their surroundings are also problematic for buildings that stand near parks or other greenery. The external reflection of trees, bushes and clouds in the sky reminds the birds of their safe environment with the possibility of shelter
and plenty of food
,” Michal Široký explains the problem.

The glass must not be completely transparent or reflect the surroundings too much

It is therefore ideal in practice to use glass that is not completely transparent, but at the same time does not have a high external reflection either. “A suitable solution is also a visible contrast in the glass in the form of a pattern created, for example, by acid etching, frit, painting or decal,” says an expert from Saint-Gobain Building Glass. “At the same time, the pattern must be clearly visible to the birds. The light plays an important role in this, which should be uniform and not create a significant external reflection,” he adds.



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Do you agree that bird protection on glass facades should be mandatory?




A dead blackbird on a wooden terrace after hitting a window-

Yes I agree. It should be a condition of approval.



Yes I agree. It should be a condition of approval.

No, but designers should think about the protection of birds.



No, but designers should think about the protection of birds.

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Tunnel test for birds

Scientists in Europe and the United States are actively engaged in the protection of birds in connection with glass facades. Martin Rössler of the Vienna Environmental Advocacy Group, for example, created a bird tunnel test that verifies the effectiveness of bird protection through glazing.

The test consists of placing two panes of glass at the end of a tunnel through which eighty to one hundred birds gradually fly through. If more than a quarter of them avoid the glass, the glass is so-called bird-friendly, i.e. it complies with the principles of bird protection,” describes Michal Široký.



Lina Mo/Shutterstock


A bird flying along the glass wall of a skyscraper

Special glass is also at the Statue of Liberty Museum

Certification of glass in the field of bird protection is provided, for example, by the American Bird Conservancy. Saint-Gobain solutions from the 4Bird series, which were used in the USA, in New York’s Statue of Liberty Museum, correspond to its standards.

Here on a small island, the use of ordinary glasses threatened to create a dangerous area for birds. Specially treated glass panes can be combined, for example, with sun protection. In this way, you will achieve not only a transparent appearance and protection against overheating of the interior, but also enough natural light,” adds Michal Široký.



Saint-Gobain Glass / Saint-Gobain Glass


Certification of glass in the field of bird protection is provided, for example, by the American Bird Conservancy

European legislation

At the same time, the so-called “bird-friendly” glass can also contribute to the comfort of the residents of the house. In contrast to the USA and Canada, where in many countries the parameters of glass facades are regulated by legislation, in European countries everything is completely based on the principle of voluntariness and recommendations.

Anyone planning a building or renovation can thus decide for themselves whether or not they will also think about the safety and protection of the birds that are singing the coming of spring when choosing glass.


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The article is in Czech

Tags: Glass facades quieter killers feathered friends time killing reduced


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