Light and dark have twisted connotations in our society. Lights are almost universally seen as good – illumination, shedding light, lighting up, and bringing safety, sunlight, and brightness. Darkness, on the other hand, is casting a shadow, lurking in the dark, and otherwise gloomy, hidden, and obscured. But what isn’t so often discussed is how damaging light can be, and how beneficial the dark is, especially for birds.
Most birders have heard of the “Lights Out” programs for cities, whereby large urban areas, typically along heavily-trafficked migration flyways, pledge to turn out skyline lights for a few days during peak migration periods. It has been found and confirmed, again and again, that these large sources of light distract and disorient migrating birds, causing exhaustion and innumerable collisions with buildings. By turning out the lights, migratory birds are able to navigate more naturally and avoid these urban obstacles.
In fact, a recent listing of the most dangerous cities for birds designates Chicago, Houston, and Dallas as the three most dangerous urban areas for migratory birds both during spring and fall migration periods. These cities are all located on migration corridors, all have intense light pollution, and all are a grave hazard for birds.
But, very few birders live in skyscrapers – many of which are enormous office buildings rather than residences – and while these cities have tremendous populations (a combined population of 6.4 million, according to 2017 statistics), there are an estimated 60 million birders or bird watchers in the United States. This means that the majority of birders live outside the boundaries of these three very dangerous cities (even if every resident of Chicago, Houston, and Dallas was a birder, 90 percent of birders still wouldn’t live in those cities). So how do lights matter to an individual birder?
While it is true that brilliantly illuminated skyscrapers positioned along migration flyways account for more per-building bird deaths per year than an individual birder’s suburban or rural home, there are far more homes than there are skyscrapers. In fact, another analysis of bird-building collision deaths compares building footprints and density with urban and suburban sprawl, with a startling conclusion. Of the estimated 600 million bird deaths each year caused by building collisions, 500,000 are easily attributed to skyscrapers. But 250,000,000 are believed to be from single-family homes and similar residences, simply by the sheer numbers of those homes. Even if a single skyscraper is responsible for more bird deaths than any one home, the cumulative number of deaths from individual homes far surpasses the dangers of a skyscraper.
This means a great deal for individual birders. Even if you don’t live or work in a skyscraper in an urban area along a migration flyway (and most of us don’t), you can help reduce the light pollution that is distracting, disorienting, and killing migratory birds – right near your own home.
- Turn off outdoor lights at dusk and keep them off all night. Many birds migrate at night, just when artificial lights are most disorienting.
- If lights are absolutely necessary, opt for motion-sensor lights only, and lower their sensitivity so they only activate when needed.
- Minimize or eliminate landscape lighting, including along driveways, walkways, fences, flowerbeds, and pools.
- Use downward-facing covers on any essential lights so the beam is more controlled and less distracting from the air.
- Turn off indoor lights that aren’t needed, or use shades, curtains, or blinds to keep the light inside instead of filtering outside.
The darker you can make your own little patch of land, the less light pollution there will be to disorient and confuse migrating birds. Better still, discuss light pollution with your neighbors (politely!) and encourage them to turn off lights to protect birds, and spread the word to your employer, family members, city council, library board, school administration, parks department, and other officials as well: tell anyone who may be able to turn off just one outdoor light. If all 60 million birders in the United States (and the hundreds of millions more around the world) were to darken just one light bulb each, the world would be a much brighter place for birds.