Red Lights: A Bat's Best Friend in Cities?

Urban illumination in Copenhagen is taking on a new hue, with one major roadway now lit in red. This change is a deliberate effort to reduce light pollution, specifically benefiting nocturnal animals like bats. Research conducted by the Netherlands Institute of Ecology demonstrated that bats remain equally active in red light and darkness, whereas white and green light substantially decrease their activity levels.

This project, spearheaded by AFRY Architects in Gladsaxe, aims to harmonize urban expansion with environmental preservation. Red LED streetlights have been installed on a primary road and cycle superhighway to minimize disruption to a nearby bat colony. Thirty bollards emit a red glow, spaced to allow light-shy species to cross safely while ensuring visibility for vehicles and cyclists.

This initiative echoes similar projects seen across Europe. Zuidhoek-Nieuwkoop in the Netherlands was an early adopter in 2018, and the UK introduced its first bat crossing with red lighting near Worcester in 2019. The research also noted that while some bat species are deterred by artificial light, others, like agile flyers, may even benefit from streetlights luring insects. Larger species flying at higher altitudes appear unaffected by typical streetlighting.