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This is Scientific American’s 60-Second Science. I’m Steve Mersky. Got a minute?

You probably missed it because you were sleeping. But one of North America's great natural phenomenon happened over the nights of mid-spring. After sundown, the skies filled with millions of birds all traveling nighttime legs of their journey north. These overnight flyways were discovered during World War 2 when Doppler radar¹ was developed. Anxious Military Official sounded false alarms over phantom² air raids but soon realized they were just watching flocks of songbirds. There were calls that each species only makes during this night  flights. This spring Jeremy Ross from Bowling³ Green State University put microphones on top of buildings in  northern Ohio to record nighttime flybys. Birds use a chain of islands to hop⁴ form Ohio across Lake Erie, to Canadian breeding grounds. Ross wants to know if   proposed wind-power farms might interfere⁵.Using the volume of each call Ross can calculate if birds are soaring safely above the blades of wind turbines. Something to consider with more wind power in the air.

Thanks for the minute for Scientific American’s 60-Second Science. I'm Steve Mersky.