A new study that used GPS tracking of Caspian terns showed that male parents carry the main responsibility for leading young birds during their first migration from the Baltic Sea to Africa.
Bird migration has fascinated human minds for millennia. How do these creatures learn to find their way to distant wintering locations? In a new study published in the journal Nature Communications, a team of researchers from Finland, Sweden and the UK tracked entire bird families with GPS devices to find out.
"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," says lead author Patrik Byholm of the University of Helsinki.
While it is well known that many birds migrate in groups, only limited information has previously been available on how individuals migrating together actually interact while travelling. Using the Caspian tern, a fish-eating waterbird that normally migrates in small groups, as a study system, the researchers found that adult males carry the main responsibility for teaching young the secrets of migration.
Guiding behavior is normally the responsibility of the biological father, although in one case a foster male adopted the role. "This is very fascinating behavior, which we really did not expect to find when setting up our study," Byholm says.
Careful analysis concerning the movements of the migrating birds showed that young individuals always remained close to an adult bird, and young birds that lost contact with their parent died.
In Caspian Sea, the young migrate together with an experienced adult to survive their first migration. The study also shows that during their first solo migration back to their breeding grounds, young terns used the same migratory routes they took with their father on their first journey south.
But the question remains unclear why the males, instead of the females, are mainly engaged in leading their young on their first migration.