Turning off building lights at night cuts bird collisions, study shows

Paper is based on 40 years of record-keeping involving 40,000 dead birds, started after an offhand remark

Turning off building lights at night can save migrating birds from crashing into buildings, a study based on decades of research has shown.

Scientists found that on nights when half the windows of a large building in Chicago were darkened, there were 11 times fewer bird collisions during spring migration and six times fewer collisions during autumn migration than when all the windows were lit.