Flying in formation saves energy. A big bird like a pelican creates a trail of turbulence in the air and this can give a following bird some lift. The effect is greatest directly behind a bird's wing tip so that is the best place for a following bird to fly. Pelicans also save about 20 per cent of their energy by mixing flapping with gliding. Aerodynamically, it is better for a bird to time its flaps with those of the bird ahead. This is why pelicans give such amazing displays of synchronized flying.