As hundreds of millions of birds head south, the invisible danger is glass

"Just after dawn in Washington, D.C., Stephanie Haley is walking a familiar downtown route, scanning the sidewalk next to office buildings. There, huddled on the ground, is a motionless olive-green songbird. It's an Acadian flycatcher, no doubt on its way to Central or South America before it slammed into a window. Haley quietly sidles up to it, gently placing a net over the bird. Then she picks the bird up, using a gloved hand."

"It begins peeping in dismay. "This is a good sign, the fluttering, which means that hopefully he's just stunned," says Haley, who volunteers with a local group called Lights Out DC, which urges people to turn off artificial lights during migration season, because these lights can attract birds and lead to deadly collisions. "I'll take him to City Wildlife and the doctors will check him out," she says, referring to the local wildlife rescue nonprofit which organizes and runs Lights Out DC."

Volunteers respond to migratory birds stunned or killed after colliding with building windows, often attracted by artificial lights during migration. Collisions can cause concussions, broken bones, and internal injuries; most birds that initially fly away later die. Window strikes are among the leading human-caused bird mortality sources in the United States, estimated at about a billion deaths annually. Research and testing identify effective glass types and window treatments that reduce collisions, but implementation faces challenges because glass is ubiquitous. Conservation groups advocate turning off lights during migration and scaling proven mitigation across buildings and urban landscapes.

Read at www.npr.org