It comes after 37 million birds flew over the state May 11, according to Lights Out Wisconsin, "far exceeding" predictions. 

As the birds race to their nesting grounds, scientists are again urging residents to turn off non-essential outdoor lights in an effort to help the birds arrive to their destination safely. 

"Certain nights bring massive surges of birds moving north, and Wisconsin sits directly in the path of some of the continent’s busiest spring migration corridors,” says Kyle Horton, Purdue University associate professor. “Turning off unnecessary lights at night is one simple step we can take to help migratory birds pass safely through our skies."

Horton uses weather radar to generate the migration forecasts along with Cornell Lab of Ornithology colleagues. 

Lights Out Wisconsin says 80% of migrating birds fly at night, and artificial outdoor lights can take them off their migration paths. 

Wisconsinites are asked to turn off non-essential outdoor lights from 11 p.m. Thursday - 6 a.m. Friday.