During the summer, families of geese will alight in the Territories to raise their young. At this time, the adults molt their feathers. This process keeps the families relatively sedentary. Female geese will tend to their young, while males stand guard around the family. Males are extremely aggressive; they'll hiss, honk and charge anything they think is threatening to their family, including armed mice.
In Legends of the Guard Volume Three, the mouse Fyodor tells a tale of a greedy gosling who eats up a lot of grain from a mill, until the mouse miller's friend from the Mouse Guard helps scare it away with a ghost disguise.