Sandpiper flock in flight
Glass windows take out billions of birds every year. Photo ©Tony Neilson

‘Smart’ windows may reduce bird carnage

It is almost impossible to comprehend the impact that windows have on birds.

According to the US Fish and Wildlife Service, 750 million birds die each year as a result of collisions with glass-clad buildings. Other research available on Google suggests the global annual glass-related death rate could exceed a billion.

Sadly, that still doesn’t compare to the devastation caused by free-ranging cats, which the American Bird Conservancy estimates at 2.4 billion annually in the US alone. (Birdlife Australia recently reported the figure for Australia at around 365 million – a million per day.)

Slow acceptance

Architects and developers are slowly accepting that they should be building more ‘bird-friendly’ structures – using new glass technologies such as ceramic frit patterns, UV coatings, shutters and screens.

But there is still a big gap between a building being ‘bird-friendly’ and one that is totally ‘bird-safe’.

New glass window technology illustration
Concept illustration showing ‘darkening’ effect of glass made with perovskites. Photo: Science

To put things in perspective, think about the last time you were at someone’s place and almost walked straight into a closed glass door – probably on the way inside from the deck or balcony. (I know I’ve done it – with glass in hand.)

The fact is that plain glass is invisible to humans – and to birds. We learn from (hard) experience and visual clues that it is not something to walk through, but birds don’t get those signals. Most birds’ first encounter with glass is their last.

New smart windows

I mention all this because there is something very new on the horizon that has strong energy-generating potential and might also make windows more obvious to birds (the latter being more a personal hope than a fact).

Science magazine reported in January on amazing new smart windows that can darken the sun and also generate electricity. They use a family of crystalline materials called perovskites.

Transforming windows

The magazine says perovskites can transform windows, keeping them clear on cold days, but turning them dark in the hot summer sun.  ‘Two research groups report that they’ve created perovskite-tinted windows that not only transition based on the temperature, but also harvest power like solar cells. The new technology could one day help cool buildings by shading out sunlight and generating power to boot.’

Although darken/lighten products have been around for some time, perovskites offer a possible route to smart windows and solar windows at the same time.


©2018 TONY NEILSON All Rights Reserved. All images are protected by Australian copyright law and cannot be downloaded or reproduced without my permission. Please contact me.



  • Steve Lewis February 1, 2018 at 5:34 PM Reply

    Great shot Tony.

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