By Craig Kerns Cornell Lab of Ornithology.jpg Birds that migrate at night and are attracted to city lights are being exposed to toxic chemicals, especially in the Gulf of Mexico, according to a study of 165 species of nocturnally migrating birds in North America. Birds that migrate at night and are attracted to city lights are being exposed to toxic chemicals, especially in the Gulf of Mexico, according to a study of 165 species of nocturnally migrating birds in North America. From disorientation and risks of fatal collisions to the destruction of ecosystems, the journeys of migrating birds ar…