By Becky Herman and Keith Bruno | Weminuche Audubon and Audubon Rockies
The focus this year on our spring bird migration has zeroed in on the negative impact of nighttime light pollution on migratory birds. Gov. Jared Polis proclaimed April 2022 as Lights Off for Bird Migration Month.
“In the coming weeks, tens of millions of birds — from statuesque sandhill cranes to smaller meadowlarks and bluebirds — will pass through our state, marking a yearly pilgrimage that Coloradans have marveled at for generations. As we celebrate Bird Migration Month this April, the Polis-Primavera administration is proud to partner with Colorado’s Audubon community to ensure that our magnificent bird populations continue to thrive, by preserving and protecting the precious natural resources these species depend on,” said Lt. Gov. Dianne Primavera.
Sky glow, the light in the sky which is predominantly caused by artificial lighting, produces a luminous background. It has the effect of reducing one’s ability to view the stars. Sky glow is highly variable depending on immediate weather conditions, quantity of dust and gas in the atmosphere, amount of light directed skyward, reflectivity of surfaces and the direction from which it is viewed. In poor weather conditions, more particles are present in the atmosphere to scatter the upward-bound light, representing a very visible effect of wasted light and wasted energy.
Migrating birds are negatively affected by sky glow in that they become confused and cannot view the stars to navigate properly. Eighty percent of migratory bird species in North America use the night sky to navigate their migratory paths between wintering and breeding grounds. They are drawn to the huge amounts of light coming upward from the earth’s surface (scientists are still trying to determine why birds are attracted to light). Flying erratically off course causes a bird undue stress, leading to lower altitudes, inefficient energy use and oftentimes locating them in unfamiliar and dangerous places, resulting in window and automobile collisions, predation, etc.
The solution is, of course, to reduce light pollution. According to Ashley Wilson, director of conservation at International Dark Sky Association (IDA), “Over the past 150 years, humans have altered this pristine, dark and quiet environment with the novel use of new technology meant to enhance our own societies.”
Unfortunately, it is increasing yearly by greater than 2 percent, according to IDA. If human behavior is inadvertently affecting the well-being of birds (and other animals), then human reaction is critical.
Lights Out Colorado (LOC) efforts were made possible through partnerships between Audubon Rockies, Denver Audubon and Colorado’s chapter of IDA.
Additionally, researchers at Colorado State University have been instrumental in providing educational understanding of nighttime bird migration through the forecasting of large migratory bird movements. BirdCast, a free migration forecasting website, allows one to not only take actions to cut light emissions in anticipation of bird movement, but also to plan nighttime bird outings for migrant or nocturnal species detections. Peak spring migration is expected from May 4-18 in eastern Colorado, where millions of birds will fly overnight to points north for summer.
There are many ways to contribute to the LOC solution. Learn more about the problem online; search websites for dark skies, light pollution, light trespass and sky glow. Advocate locally for careful attention to the planning process for public and private outdoor lighting. At your home or place of business, turn off all outdoor lighting whenever possible and remove any unnecessary flood lighting. Where lighting is necessary, use motion sensors and downward-facing lights. Use drapes/shades after dark and avoid leaving lights on the upper stories of buildings for extended periods. No surprise, your electric bill will decrease as you take these actions to benefit the night sky.
Further highlighting the importance of this issue, the globally recognized World Migratory Bird Day occurs May 14, with 2022’s theme is “Dim the Lights for Birds at Night.” For this “Global Big Day,” community members are encouraged to report bird observations on eBird (go to ebird.org to learn more), whether from the comfort of your backyard or elsewhere. By doing so, we create a real-time snapshot of the health and breadth of bird populations.
To get involved with our local Audubon chapter, go to weminucheaudubon.org, and to learn more about LOC, visit lights-out-colorado.idacolorado.xyz/.