Lights Out

The Impact of Light Pollution on Wildlife and Human Health

From hummingbirds and warblers to sparrows and geese, millions of birds migrate across North America every year, covering hundreds to thousands of miles. Most of these birds, some that weigh as little as half an ounce, make this remarkable and perilous journey at night, visualizing the magnetic pull of the earth and using the moon and stars to set their course. By reducing skyglow over our cities, we can help them make it to their destinations safely.

Migration by moonlight, photo by Jurgen

As migrating birds pass over brightly lit cities, skyglow drowns out the stars, confusing them and luring them into urban areas. Once trapped in the windowed maze of the city, birds either hit buildings directly or circle them until they collapse from exhaustion. Lights Out programs help to prevent birds from being attracted to urban areas. In Chicago, one Lights Out building showed an 80 percent decrease in strike rates after joining the Lights Out movement. Turning off unnecessary overnight lighting also helps us save energy (and money!), reduce our carbon footprint, and protect our view of the stars!

Take the pledge to go Lights Out for birds, other wildlife and human health

Pledge to reduce your unnecessary lighting and receive a free metal yard sign or a vinyl window cling! The sign shows your neighbors that you have taken the pledge to save energy, save birds and see stars!

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The Night is Habitat

In addition to hosting migratory birds on their way north or south, the night is actual habitat. Biological systems evolved on this planet in cycles of light and dark. When we light the night, we are in fact fragmenting habitat occupied by nocturnal species. We are also tampering with highly complex ecosystems that rely on carefully timed circadian rhythms (light/dark cycles) that govern sleep, mating, migration, flowering, hunting, hibernation, plant budding and flowering, leaf drop, and the list goes on.

It is easy to minimize light trespass with well-designed lighting, and still provide all the light that we need. Portland Audubon is working throughout the region to ensure that we are designing our built landscape for ecological resilience into the future.

Western Screech-Owl – Version 2
Western Screech-Owl at dusk, photo by Rhett Wilkins

Human Health

Humans need the dark too! The American Medical Association recommends steering clear of blue-rich white LED streetlights to “minimize potential harmful human health and environmental effects.” The 2014 AMA Study suggests that exposure to artificial light at night may increase the risk of cardiovascular disease, depression, sleep disorders, obesity and breast cancer. Research out of the Stanford Sleep Epidemiology Lab shows that street lighting can delay sleep cycles and reduce the quality of our sleep. Research out of the University of South Florida shows that birds exposed to artificial light incubate West Nile Virus for twice as long, potentially increasing the occurrence of West Nile Virus in our cities. Increased risk factors for diabetes, cardiovascular disease, impaired sleep, and higher risk of transmissible disease exposure may be most impactful to communities that are already at elevated risk of exposure to harmful pollutants, including the elderly, low-income communities and communities of color.

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Light Pollution in Portland, Photo by Ryan Harvey

Conversion to LED

There is a gold rush conversion to LED lighting around the globe. While LEDs are great for saving energy and money, not all LEDs are safe for birds, wildlife, and human health and vision.

Research on blue-rich white light LEDs shows them to be a serious risk, both to our environment and to human health. Luckily there are warm light LED alternatives and emerging best practices in lighting design that include: fully-shielded light fixtures, aiming light down, and carefully considering lighting levels and spectral output. Read more here.

Tilikum Crossing, photo by Old White Truck

Lights Out Portland

Building owners and residents can help by voluntarily turning off unnecessary overnight lighting during migration seasons!

How Can Building Owners and Managers Help?

Buildings can extinguish unnecessary overnight lighting from late August through mid-November (fall) and mid-March through early June (spring). Top priority is turning off exterior, ornamental and rooftop architectural lighting. Buildings can also extinguish interior lighting on upper floors, move maintenance and cleaning activities to daytime hours, turn off upward-directed sign lighting and make sure that outdoor lights are properly shielded.  Take the Pledge to Go Lights Out or contact Mary Coolidge.

How Can Residents Help?

Light Pollution is the accumulation of many sources of poorly designed or excessive lighting. We can all contribute to the solution by evaluating the way we use light. Take the Pledge to go Lights Out today! Make sure your exterior light fixtures are well-shielded and not overly bright. Select warm LED bulbs that are under a 3,000 Kelvin rating. During migration seasons, draw blinds or curtains to reduce light spill that contributes to sky glow. Looking for good lighting? The International Dark-sky Association has a Fixture Seal of Approval program!

If birds are hitting your windows, there are a variety of ways to reduce strikes at home year-round.

Need a Cash Incentive?

Energy Trust of Oregon offers incentives to increase the energy-efficiency of lighting fixtures and controls. Visit Energy Trust of Oregon to learn more.

Worried About Safety?

Read up on some interesting research that urges us to think more critically about the relationship between lighting and safety: