If you look to the skies at this time of the year you may see something similar to this. Migrating American White Pelicans congregate into swirling and undulating masses of birds that flash white or black depending upon the orientation of the soaring pelicans. The groupings can be quite large and tend to be very slow moving. Eventually, the pelicans will reform into more typical V-formations and continue on their way at a substantially quicker rate.