Lights Out Alert forecast for tonight, May 11, across entire state

Turn off outside lights overnight to save birds and sign up for reminders 

Black-throated Blue Warbler by Kelly Colgan Azar

Media Contacts:

Alicia King, Lights Out Wisconsin and Executive Director Wisconsin Society for Ornithology, 907-268-0124,  executive.director@wsobirds.org

Brenna Marsicek, Lights Out Wisconsin and Outreach Director Southern Wisconsin Bird Alliance, 608-255-2473; bmarsicek@swibirds.org

Carol Wesley, Lights Out Wisconsin and Kickapoo Valley Dark Sky Initiative director, carolwjean124@gmail.com

Scientists forecast high levels of bird migration tonight --16.1 million birds over Wisconsin and 383 million over the continental U.S.—and urge people to turn off outside lights overnight.

Madison, May 11, 2026 – Extremely high bird migration is expected over Wisconsin tonight, May 11, and scientists from the Cornell Lab of Ornithology and Purdue University forecast a Lights Out Alert statewide.

People are urged to turn off non-essential outdoor lights from 11 p.m. to 6 a.m. tonight, and ideally, throughout the bird migration season ending in mid-June.  

Eighty percent of migrating birds fly at night, and artificial light can lure them off their migration paths into urban areas where they face more hazards, including windows. Birds flying into windows kill up to 3.5 billion birds every year in the United States. It is regarded as a leading reason why nearly 30% of North American birds have disappeared since 1970.

Purdue and Cornell scientists forecasting the intensity of bird migration over the continental U.S. using weather radar predict 16.1 million birds will fly over Wisconsin tonight, May 11, and a total of 383 million birds across the lower 48 states. Forecasts are updated every six hours.

The scientists issue a Lights Out Alert whenever bird traffic is within the top 10% of nights, about 8 to 10 nights a season. These nights account for about 50% of the migration traffic.

Appleton, La Crosse, Madison and Milwaukee are among the 216 cities nationally where alerts are now available. Sign up to get email alerts for those cities on nights when high bird migration is forecast. People living outside these cities should sign up for the city closest to them or another Midwestern city near them, according to Adriaan Dokter, research associate and project lead for BirdCast at the Cornell Lab of Ornithology. See a map showing locations.

Lights Out Wisconsin formed in fall 2025 to reduce light pollution when dark skies matter most for wildlife and people. Promoting signups for Lights Out Alerts issued by Cornell and Purdue scientists is a key strategy to achieve that goal of bird conservation. People can subscribe to get the alerts through the Lights Out Wisconsin website.

Peak bird migration in Wisconsin historically begins the first week in May (a little later in northern Wisconsin) and lasts about two weeks. See peak migration periods for Wisconsin communities and learn more about Lights Out Alerts on the Purdue Aeroeco Lab webpage for Wisconsin.