A flock of flying geese is referred to as a skein of geese. When geese are not in flight, they are referred to as a gaggle.
A “V”-shaped skein of geese is also known as a wedge. In addition to geese, ducks and other migratory birds that move in flocks are also referred to as skeining.
To conserve energy, geese fly in a “V” pattern to reduce wind resistance. The configuration also aids the geese in keeping track of each individual bird. By travelling in this manner, a flock of geese is able to fly further and for longer distances without becoming as fatigued.