Excessive exterior lighting isn’t just wasting energy – it may be harming migrating birds. Cut down your energy spending and ensure safe passage during migration season by joining a local Lights Out initiative.
Building Features and Birds
Buildings pose a number of obstacles for migrating birds, millions of which die each year from building-related accidents, notes David Willard, President of the Chicago Audubon Society.
“Birds that migrate at night orient their flights relative to the stars, much as mariners once did in crossing the seas, except that for birds the ability to do this is innate,” Willard explains. “One thought is that all of the artificial lights are like additional stars that mess up the birds’ orientation. There also seems to be a tendency to fly toward light like moths to a candlelight – birds will fly into the beam of a searchlight and circle it until they drop from exhaustion. Also, when birds are attracted into the city by lights, they’re then confronted with glass that they do not see and collisions occur.”
According to Annette Prince, Director of Chicago Bird Collision Monitors, the most dangerous building and lighting designs for birds include:
- Reflective glass surfaces, which cause birds to fly toward the reflections of the sky, trees and other landscaping
- Transparent glass buildings, railings or skyways – they appear like an area a bird could fly through
- Bright display lighting kept illuminated at night, which can lure birds toward other building hazards
- Lobbies that are brightly lit at night and contain interior plants and fountains that birds may try to fly to after spotting it through the glass
“When the glass facade is broken up into much smaller panes, that can reduce the number of birds striking,” adds Willard. “Many bird strikes in downtown Chicago, for example, are during the day when lights are not the problem. Some architects are using new glass types that have patterns that discourage birds from striking.”
How Lights Out Works
Created by the national Audubon Society and piloted in Chicago in 1999, Lights Out is a simple initiative that asks building owners and managers to turn off extra lighting during the months that migrating birds are flying overhead. Fewer distractions from excess light means more birds can safely travel between their nesting and wintering grounds, and as a bonus, putting out less light at night will help reduce energy consumption.
Birds migrate during most parts of the year, Prince explains, so consult local conservation organizations about the heaviest migration periods in your area and plan your outdoor lighting practices accordingly. “The longer the period that is set, the more birds will be protected,” Prince says. The Cornell Laboratory of Ornithology also offers eBird, a mobile and web-based resource that tracks arrival and departure times during migration.
You can also tweak whatever lighting is left on to make it less dangerous, Prince adds. “Any designs that keep lighting from streaming up into the night sky are best,” explains Prince. “Also avoid using LED lighting with blue-rich white light – that will decrease the brightness of night lighting and avoid the deleterious effects of blue spectrum emissions at night.”
It’s difficult to estimate how many birds you can save due to the number of variables involved, but Prince named one Chicago study that compared bird strikes at one building with its lights on vs. lights off. “There was an 85 to 90% reduction in bird strikes,” Prince says. “If this is translated across all buildings leaving lights off, the estimates are tens of thousands of birds saved. We no longer have huge strikes in one night at one building where the lights were left on, as occurred prior to the light reduction program.”
Janelle Penny email@example.com is senior editor of BUILDINGS.