The shortest distance between two points is the straight line, connecting the points. Surely, the hummingbird, being a disciplined rational creature, will choose the straight line to fly. So, this problem is about a triangle. You may even make one step forward and to see (or to guess/to recognize) a right-angled triangle here. As soon as you identify a right angled triangle, apply the Pythagorean formula d == = = 13 meters. ANSWER (5,12,13) is a Pythagorean triple, next after (3,4,5).