A team of researchers studied a bird species called the Caspian tern. Using GPS, the team followed their annual migration from the Baltic Sea to the African tropics. One researcher explained the purpose of the project: "We wanted to get a better idea of how the migratory skills of birds are passed from one generation to another in a species where individuals normally migrate together."

It has long been known that birds migrate communally, as witnessed by the annual migrations of large flocks of geese during the North American spring and fall seasons. However, little is known about interactions among the members of traveling flocks.

Having studied the Caspian tern's migration behavior, the research team found that father terns teach their young about the secrets of migration while defending them from dangers they encounter along the way. One researcher said. "This is very fascinating behavior, which we really did not expect to find when setting up our study."

The scientists even observed a case of a foster father bird filling in for a father's role. Young birds always stayed close to the adult bird. Indeed, young strays died. The authors of the study suggest that young birds must remain in contact with a parent during a first foray to winter grounds.

The team also found that when the young birds make their first solo return flight to breeding grounds in Europe, they took the same migratory routes on which they were accompanied by their fathers. In Caspian terns, migration knowledge is inherited through culture from one generation to another. This has consequences on the decisions individuals make years after they first migrated with their father.