Most of the world’s species of geese migrate every year in search of warmer weather by following well-defined migratory routes known as migration corridors, with snow geese migrating over 5,000 miles at speeds of 50 miles per hour each year. In areas located within the migratory corridor of snow geese, it is common to see flocks numbering thousands of geese resting together.
Migrating geese tend to flock in groups numbering tens of thousands. While some species such as the snow geese are easily recognizable during flight, since they fly in V-shaped formations, others such as brant geese fly in clusters low to the ground. During their migration, geese flocks practice "pond hopping," which means they fly from one pond to the next to secure water, food and safety.
However, not all geese migrate. Some geese are known as resident geese, meaning they don't need to migrate and can therefore stay in one location permanently. This is usually the case with geese that populate areas with year-round temperate weather. While resident geese don't become migratory geese, a migratory goose that is injured in flight might become a resident goose by necessity. The migratory season for geese lasts from October to March.