Long ago there were some very creative ideas about where birds disappeared to during the winter months. Did birds migrate to the moon? Morph into other species? Hibernate underwater? To answer these questions, people began marking birds to see if an individual specimen returned the next year. This technique eventually led to a highly effective analog technology known as banding, or ringing, that is widely used today. Developed at the turn of the 20th century, bird banding uses metal or colored leg bands or colored wing tags marked with a unique number or alpha-code as a method for documenting re-encounters of individual birds. Bands are affordable, dependable and extremely lightweight—the smallest weigh only 0.001 gram—and can be used on all sizes and species of birds, from hummingbirds to eagles. In North America, the US Geological Survey’s Bird Banding Lab, established in 1920 by visionary scientists, is a cornerstone for avian conservation and...