Of all the birds Miranda Brandon collected on the streets of Minneapolis and St. Paul in 2013, it was perhaps the Ruby-throated Hummingbird that hurt the worst. Ruby-throats, which weigh less than a nickel, can fly up to 2,500 miles from Canada to Central America during fall migration, including a nonstop push across the 500-mile-wide Gulf of Mexico. They hover and fly—forward, backward, even upside down—their wings fluttering up to 50 times per second, at speeds reaching 40 miles an hour, and their hearts thumping as fast as 1,220 beats per minute. Considering those magnificent feats, Brandon, a 34-year-old who recently earned a master of fine arts degree from the University of Minnesota, felt especially sorrowful upon discovering the Ruby-throat lying dead on the concrete, one more building-related casualty. She found the bird, and dozens of others, while volunteering with 蜜柚APP Minnesota’s Project BirdSafe, which in 2007 began monitoring bird deaths due to window...