Birds and buildings are often a lethal combination. In the UK alone it is estimated that up to 100 million birds are affected by collisions every year. The statistics are particularly staggering in the US, where an academic report has found that as many as a billion birds die each year when they collide with buildings, especially glass-covered or illuminated skyscrapers.
The reasons behind these mass fatalities are not difficult to fathom. It often happens because of reflections in the glass, whereby the bird doesn’t realise that the sky or trees it can see is just a reflection and so crashes into the glass as it tries to fly to them.
It’s an issue as old as glass itself, but it’s become increasingly problematic – for building owners and of course for birds – as the number of skyscrapers springing up in cities has greatly expanded over recent decades.
Confronting the problem
Aside from the obvious ethical considerations, not taking steps to protect local bird populations can cost facilities managers both time and money. For example, when a bird collides with a window, it often leaves an unsightly print on the glass – meaning that facilities managers may need to more regularly hire external contractors to regularly clean the windows, increasing maintenance costs.
Any birds that fall to the ground following collisions will also need to be cleared away, particularly as they can attract pests such as flies and rats. This naturally increases maintenance costs further.
Not only that, but bird safety has become an increasingly pressing regulatory issue for building owners. The US and Canada have led the way in this respect, with the US Congress introducing the Bird-Safe Buildings Act (2017) which stipulates that at least 90% of the exposed façade material on new public buildings (up to 40 feet – the primary bird-collision zone) should either be made up of glass employing bird-safe elements, or not be made of glass at all.
Given that more countries around the world – including the UK – are likely to follow suit in their regulations, bird safety should be a consideration for every building owner.
Our solution: Pilkington AviSafe™
Various techniques have been tried and tested to stop birds flying into reflections, some more effective than others. One of the most obvious solutions has been for glass makers to add visible shapes or decoration to the glass.
This has been highly effective at stopping bird collisions, but it simultaneously undermines the purpose of the glass as a transparent window surface. This option is usually not favoured by architects and building owners who want their buildings to feature crisp, clear glass façades free of any blemishes or markings.
The key then is to create something the birds can see but which humans can’t – and that’s where our expertise comes in. Indeed the technical team at Pilkington are experts at manipulating the absorptive and reflective properties of complex coatings, and it is through this specialism that we have developed Pilkington AviSafe™ glass.
Simon Slade, Principal Technologist at Pilkington UK and himself a keen ornithologist, has led the field testing of the Pilkington AviSafe™ project by working closely with avian experts to understand how birds see the world – in particular how they use ultra-violet light (which is invisible to humans) and wavelengths we can barely see.
Using this knowledge we have developed a coating that combines UV reflective and anti-reflective material in a pattern that disrupts the reflection, meaning that a bird instead sees a barrier. The coating and pattern we’ve developed is barely visible to humans, especially from inside the building.
Results and future considerations
We’ve honed this solution through final-stage trials, including in applications at local nature reserves in Lancashire such as at Mere Sands Wood LWT reserve. In doing so, we’ve been able to work with staff with a detailed knowledge of local bird populations to understand how birds are responding to the glass.
Our expertise in developing this new coating has shone through in trials. While other glass manufacturers have produced and marketed UV-patterned glass as ‘bird protecting’, field trials of these products haven’t necessarily been as effective at stopping birds from colliding with them as expected.
By contrast trials of Pilkington AviSafe™, conducted by independent zoologists at bird ringing stations in Europe and America, found that our UV-enhanced glass was as effective at deterring birds from flying into reflections as glass screen printed with a fully visible pattern of dots. It explains why Pilkington AviSafe™ was recognised at the glass industry’s Glass Focus 2018 awards with the ‘Innovative Solution’ award in November 2018.
We don’t want to stop there either. We know that as the built environment becomes more complex, the challenges facing architects and building owners will grow in complexity too. That’s why we want to continue developing Pilkington AviSafe™ as a coating that could be applied in other applications such as solar control, safety and security, and noise control.
Simon Slade, Principal Technologist at Pilkington UK, commented: “Bird safety is an extremely important issue, both from a conservation point of view and a building maintenance point of view. Our expertise in coatings, and in developing highly effective solutions like Pilkington AviSafe™, will continue to guide our work in this area going forward.”