Ian Austen, reporting for the New York Times:
There is no precise ranking of the world’s most deadly cities for migratory birds, but Toronto is considered a top contender for the title. When a British nature documentary crew wanted to film birds killed by crashes into glass, Daniel Klem Jr., an ornithologist at Muhlenberg College in Allentown, Pa., who has been studying the issue for about 40 years, directed them here, where huge numbers of birds streaking through the skies one moment can be plummeting toward the concrete the next.