A year ago, Philips Lighting (now called Signify) announced results of a study which showed that its ClearField red LED lighting didn't disrupt the behaviour of bats – unlike traditional streetlights. Now, the Dutch town of Zuidhoek-Nieuwkoop has become the first place in the world to use the system.
Many species of bats have evolved to forage in near-complete darkness, and as a result tend to shy away from white LED and yellowish sodium vapor streetlights. Given that cities are full of these lights, the areas in which the animals can hunt effectively are quite limited. Additionally, the insects that the bats feed upon are attracted to the lights, drawing them into areas where the bats don't want to go.
With that in mind, Philips conducted experiments in 2017, in which it mounted red, green and white LED lights on poles in what was otherwise a dark and undisturbed natural habitat. The red lights incorporated the company's proprietary ClearField technology, which was developed in collaboration with the Netherlands' University of Wageningen and other non-governmental organizations.
All three colors were of an intensity that is commonly used to illuminate country roads.
It was found that while bats avoided the green and white lights, they were undisturbed by the red ones. According to Signify, this was because those lights utilize "a special light recipe that is perceived by bats as darkness, yet which provides enough illumination for residents," adding that the lights "use a wavelength that doesn't interfere with a bat's internal compass."
Zuidhoek-Nieuwkoop, which is a known feeding ground for rare species of bats, has now installed the lights on the streets of an 89-house sustainable housing development. Installation of the system was completed this Tuesday.
