How an excited naturalist and a well-intentioned town came to collide in the night.
Ryan Rice
Screech owls prefer established cavities for nesting, particularly those in dark places.
One night, not all that long ago, a streetlight went on in a downtown Boone, North Carolina, neighborhood. Its bulb had been broken for years, creating a snaggletooth gap in the bright smile of lights that curve around the block. In a lot of places, a dormant streetlight’s activation would be seen as cause for celebration. But, for the residents of this neighborhood, it was viewed as a life-or-death concern demanding immediate attention.
Richard Gray, professional astronomer, was the first to notice the new bulb. This seems fitting, since an astronomer’s job is, at root, to study light. Astronomers take images of nebulae, swirls of dark and bright, and interpret what’s happening in the interplay. As a researcher, Richard uses spectroscopes to break stellar light into component colors the way prisms reveal rainbows, with hues suggesting a star’s age and velocity.
Years ago, he had to travel winding mountain roads to access the telescopes at Appalachian State University’s Dark Sky Observatory. Now he just logs onto apps from his computer, which gives him the power to remotely access telescopes from his house. The whole endeavor could be handled at a distance via screens and buttons, but he still often steps into his yard beforehand to gauge local weather.
It was during one of these regular surveys that he noticed a streetlight-maintenance truck. In recent years, the town has phased out traditional lights for more energy-efficient bulbs. County workers weren’t aware that this streetlight had been nonfunctional for years; they were just going about their assignment.
The additional artificial light would have, under any circumstances, been worrisome for a man who spends his life attempting to decipher starlight. But Richard was doubly worried, because the light emitted wasn’t only interrupting his stargazing—it was reaching into a wooded lot across the street, all the way to his newly installed owl-nesting box. For the last few years, Richard and his wife had enjoyed a screech owl singing them to sleep, and he had just built a nesting box in appreciation. As a lifelong birder, he knew that screech owls don’t craft nests of twigs and twine. They’re cavity nesters who tend to find already established holes in trees. So in places where mature trees have fallen to development, owl boxes can be helpful.
After Richard put the box up, he’d waited for owls to take him up on the offer of shelter. And he’d waited—and waited. Then, just before that streetlight went back on, a screech owl pair had shown up. It’s common practice for owls to house hunt before settling down, so the light had particularly bad timing. The relationship he’d worked to establish was acutely threatened. The new bulb was, like almost all newly installed bulbs, a white-light-emitting diode (LED). And, like many LED lights, it produced blue-rich white light. This type of light isn’t just the most damaging for astronomers’ sight; it’s one of the most biologically confusing for wildlife, since animals read blue light as a signal to enact daytime behaviors.
Astronomers tend to think of light not in generalities, but by wavelength: Red waves are long and easygoing, blue are short and energetic. We might dismiss sunlight as a generic white, but it’s violet and blue and green and yellow and orange and red. We’re surrounded by rainbows every day, we just can’t always make out light’s diversity—mainly because blue wavelengths are particularly pushy.
When animals are blasted with blue light at night, their bodies naturally read it as daylight. This is why, with an increase in light pollution, biological systems three billion years in the making are starting to misalign. Animals get amped for their respective activities out of sync. Artificial light literally puts us on different wavelengths.
In contrast, warm-tone spectra tend to be read by animal bodies for what they are: more easygoing energy. Campfires and old-fashioned incandescent bulbs tend to pool light where they’re located. But even in situations where streetlights point downward, as responsible guides suggest, blue light tends to bounce skyward.
Advanced LED bulbs provide more light with less energy. This has led to near-universal adoption of blue-rich LEDs, though the technology is capable of other colors. Life scientists generally agree that LEDs with high blue content have larger biological impact than the bulbs that came before them. And the potential energy conservation of using this technology has largely been negated by human behavior. Instead of using less energy after switching to LED lights, people have, the world over, started using even more energy for ever-brighter illumination, as if we’ve collectively decided that, since the light is energy-efficient, we might as well produce more of it.
Many news stories about light pollution present it as having increased roughly 50 percent over the past 25 years. But people familiar with satellite technology have brought to attention the fact that some of the equipment that’s been used to gather data is not sensitive to blue wavelengths, which are on their way to global domination. With blue-rich LEDs taken into consideration, some scientists suggest that, in certain places, artificial light pollution has more realistically increased 270 to 400 percent during the past 25 years.
Interestingly, as outdoor blue light has proliferated, literally under radar, our awareness of it indoors has increased. During the pandemic, when nearly every interaction with people outside of a given household was conducted via screens, the popularity of glasses with blue-blocking lenses grew. We know blue light is harmful, but it seems impossible to get away from it. After all, when Richard stepped away from his computer on that first LED-lit night, he found that the same blue spectra that he’d been trying to take a break from had swallowed his entire house from the outside.
He’d planned to watch the miracle of owls’ seldom-observed life cycles unfold with the same close attention that he gives young stars through telescopes. Now, every tender act he’d hoped to witness was under siege. Frantic to find an off switch, he started making calls. To public officials. To neighbors who might help him create an uproar. But in the end, no uproar was needed. Once administrators learned that a brooding pair might be disturbed by the streetlight—which they’d thought, if anything, human residents would consider an upgrade—workers arrived within 74 hours to remove the bulb, returning the neighborhood to the level of darkness it had previously enjoyed.
Municipal administrators had been trying to do the right thing with those LEDs. They had crunched facts and figures, but they had not absorbed the true cost of pelting energy against everything in the streetlight’s radius. Unfortunately, the town’s quick response was still too late. By the time the streetlight went dark, those house-hunting owls had already fled.
About This Story
This story is an excerpt adapted with permission from Leigh Ann Henion’s recently published book, “Night Magic: Adventures Among Glowworms, Moon Gardens, and Other Marvels of the Dark” (Algonquin Books). In “Night Magic,” the owls ultimately have a happy ending.
Henion is also the author of “Phenomenal: A Hesitant Adventurer’s Search for Wonder in the Natural World.” Her writing has appeared in The New York Times, The Washington Post, Smithsonian and a variety of other publications. She lives in the mountains of North Carolina.
For more information: leighannhenion.com/books.
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