Getting your Trinity Audio player ready...
A report from Cornell University’s Lab of Ornithology ranked Chicago as the most dangerous city for migratory birds.
Bird migration danger
Zbigniew Bzdak/Chicago Tribune
Mary Hennen, assistant collections manager for birds at the Field Museum, opens drawers filled with white-throated sparrows that died in window collisions in Chicago. White-throated sparrows are especially susceptible to colliding with buildings. 
