Starlings’ migration: It’s all in their genes

To find out how migrating birds find their way, sparrows were relocated from autumn stopovers along the Dutch North Sea coast to Switzerland (red, 1948–1957) and Spain (blue, 1959–1962). Credit: Biology Letters (2024).

Researchers have discovered that young starlings know how to find their wintering grounds without following older, more experienced birds.

Even though starlings are social creatures, they do not learn their migration routes from each other.

This surprising discovery has been confirmed by a team of scientists from the Netherlands Institute of Ecology (NIOO-KNAW) and the Swiss Ornithological Institute (Vogelwarte Sempach) and is published in the journal Biology Letters.

The question of how birds know where to migrate has puzzled people for centuries.

In the 1950s and 1960s, biologist Albert Perdeck conducted a famous experiment to find answers.

He relocated thousands of migrating starlings from the Netherlands to Switzerland and Spain by plane.

By tracking the birds’ movements, he found that young and adult starlings used different strategies to reach their winter destinations.

Recently, researchers revisited Perdeck’s experiment and added new data to settle a long-standing debate.

They found that adult starlings, aware of their new location, adjusted their migratory paths to reach their usual wintering areas.

However, young starlings, following their natural instincts, continued in a south-westerly direction, ending up in southern France and Spain instead of their intended destinations.

For years, experts have debated whether young starlings learn their migration routes from older birds or if they inherit this knowledge.

Some believed that relocated young starlings might join local flocks and learn the way from their new friends. If this were true, it would mean that migration routes are learned rather than inherited.

To resolve this debate, the team retrieved historical data from Perdeck’s experiments and compared it with the migratory behavior of local Swiss and Spanish starlings. They found that the relocated starlings’ migration paths differed from those of the local birds.

This means that starlings do not simply copy the migration routes of other birds. Instead, their migration behavior is inherited, not learned.

Interestingly, a recent study showed that starlings migrate at night. This supports the idea that they do not follow other birds, as it would be difficult to do so in the dark.

Understanding whether migratory behavior is inherited or learned is crucial, especially with rapid changes in climate and land use. Inherited behaviors are less adaptable to change. Although starlings are numerous and have adapted well to human-dominated landscapes, their migratory behavior is likely less flexible.

Lead scientist Henk van der Jeugd emphasizes the importance of understanding this, as it can impact how we protect and support these birds in the future.

This research highlights the incredible instinctual abilities of starlings and the importance of genetic inheritance in their migratory behavior.