Which types of waterfowl generally migrate in family units?

Geese and swans are known for migrating in family units, particularly because they have strong familial bonds that are maintained throughout their lives. During migration, these waterfowl often travel together as a cohesive family group, which can provide safety in numbers and facilitate the learning of migratory routes from parents to young.

Geese, for instance, typically form strong pair bonds and travel with their offspring during migration. This behavior can be very advantageous as it allows for the young birds to gain experience while relying on the adult birds for guidance and protection.

Swans also exhibit similar patterns, where they travel in family groups, often remaining together as a family unit until the young are mature enough to fend for themselves.

In contrast, the other options do not typically demonstrate this family-centric migratory behavior. For instance, while ducks may migrate in groups, these groups are generally not composed exclusively of family units but rather mixed flocks. Quail and pheasants are terrestrial birds and do not share the migratory behaviors associated with waterfowl. Thus, geese and swans clearly stand out for their tendency to migrate in family units.