An exhibition center on Chicago' lakefront is modifying its windows to prevent bird strikes after hundreds of birds crashed into the building in one night last fall. Nearly 1,000 migrating songbirds died after colliding with the McCormick Place Lakeside Center's windows in October. Birds don't see clear or reflective glass and don't understand it is a lethal barrier. Bright lights from buildings attract and confuse them. The Chicago Tribune reports that the center began a $1.2 million effort in June to install window films etched with dots that make it easier for birds to distinguish windows from nature.