Weather conditions and time of year are combining this week for a very large push of migratory birds across Wisconsin.
And in response bird advocates are urging state residents to turn off outdoor lights on the night of Oct. 10.
Most migratory birds fly at night, and artificial light can disorient them, drawing them into developed areas where they face greater risks, especially from window collisions, according to Brenna Marsicek and Lisa Gaumnitz, representatives for Lights Out Wisconsin, a bird conservation and dark sky advocacy group.
BirdCast, a product of the Cornell Lab of Ornithology, Colorado State University and University of Massachusetts Amherst, is predicting 367 million birds in flight across the U.S. on the night of Oct. 10.
The seasonal movement is traditional, with hundreds of bird species traveling south prior to winter. A push of cold air from the north and northwest this week has helped create a large pulse of migratory birds moving through Wisconsin and many other states.
Lights Out Wisconsin recommends state residents turn off any unnecessary outdoor lights as well as draw window shades from 11 p.m. to 6 a.m. during periods of peak bird migration.
“Even one night of darker skies can save thousands of birds by spurring them to fly on to less developed areas with fewer windows and other hazards to encounter in daytime,” according to Lights Out Wisconsin.
The AeroEco Lab at Purdue University also stresses the importance of “lights out” measures to assist bird migrations.
Turning off lights reduces collision risk by lowering skyglow and drawing fewer birds into brightly lit urban cores as well as protects habitat quality by keeping nights darker for resting birds near important stopover hotspots, according to the lab.
It notes a direct financial benefit to humans, too: it helps homeowners and others by conserving energy and saving money by dimming or switching off non-essential lighting.
Lights Out Wisconsin is a bird conservation and dark sky initiative launched in 2025.
Its stated goal is “to protect birds, reduce light pollution, and protect the night sky in Wisconsin.”
The campaign is coordinated by nine Wisconsin organizations: Bird City Wisconsin, Dark Sky Wisconsin, Driftless Birds, Kickapoo Valley Dark Sky Initiative, Lake Michigan Bird Observatory, SOS Save Our Songbirds, Southern Wisconsin Bird Alliance, Wisconsin Bird Conservation Partnership and Wisconsin Society for Ornithology.
It receives financial support from the National Audubon Society.
Lights Out Wisconsin sends out email alerts prior to what it calls “high-risk mass migration events.”
To sign up for email alerts or learn more about the campaign, visit lightsoutwi.org.
This article originally appeared on Milwaukee Journal Sentinel: Wisconsin residents urged to turn off outside lights Oct. 10 to help protect migratory birds
Reporting by Paul A. Smith, Milwaukee Journal Sentinel / Milwaukee Journal Sentinel
USA TODAY Network via Reuters Connect
