Habitats that are good for birds are good for people, too.
Sometimes it seems like cities were designed to kill birds. Take for instance the single night in October when more than 1,000 birds were killed when they collided with buildings in the city of Philadelphia. Due to a combination of confusing reflections from building windows, disorienting light pollution, and the location of tall buildings in the direct flight paths and habitats of many birds, deadly collisions—sometimes in mass numbers—are depressingly common. Researchers estimate that collisions with buildings cause up to one billion bird deaths in the United States every year.