Wisconsin Sees Massive Nighttime Bird Migration Surge, Raising Concerns

According to the BirdCast migration dashboard, millions of birds have been migrating across Wisconsin every night since late August 2025. The largest migration surge so far this season occurred on September 17, when more than 52 million birds migrated over the state.

While migration has ebbed slightly in the past week, nearly 2 million birds still migrated over Wisconsin on September 29, including almost 14,000 over Milwaukee County. Experts warn that the migratory and hunting season for birds in the region can start as early as August and run as late as November, with migration numbers typically peaking in late October.

To help protect these migrating birds, BirdCast is urging the public to turn off non-essential lights around their homes from 11 p.m. to 6 a.m. during times of high migration. Bright lights can attract and disorient birds, sometimes leading them to fatally collide with buildings and other structures. The Wisconsin Department of Natural Resources also recommends supporting migrating birds by reporting sightings and providing food and habitat.