Have you ever looked up the sky and wondered why birds tend to fly in V formation? A group of scientists have followed a group of Northern Ibises to study their flying positions and flapping dynamics. From their experimental data, they have found concrete data that support a longstanding theory that the purpose of V formation is to save energy.
The leading bird tends to have a faster heart rate compared to the trailing bird. What the data suggests is that the leading bird creates a wind vortex, which helps the trailing bird to stay in air without spending the same amount of energy. Thus, the trailing bird does not have to flap as hard, though the motion needs to be coordinated with the vortex to gain the upward momentum.