In the 1990s, train engineers in Japan built trains able to travel nearly 170 miles per hour. The problem was that when the trains exited a tunnel, the air in front of their bullet-shaped noses expanded rapidly, creating a loud “tunnel boom.” The chief engineer, a birder, looked to the shape of a kingfisher’s bill to design long, narrow train noses that parted the air. The trains became both quieter and more efficient. Learn more at BirdNote.org.