Avian Rest Stops

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Everyone needs a little pitstop during long journeys. So do birds.

A new study found that some migratory birds occasionally take breaks on long migration routes to boost their immunity, the Washington Post reported.

A research team closely studied a group of migratory birds making stops on the German Island of Heligoland during the fall of 2021. The island is a popular stopover for avians on the move in autumn.

The researchers captured, tagged, and released the birds on the island during the study. They ended up sampling the blood of 96 birds twice throughout the stopovers, which ranged from an hour to a little more than two weeks.

Scientists previously believed that birds would sometimes stop during their marathon flights to build up their fat reserves.

Instead, their findings showed that the birds’ immune systems became more efficient at fighting pathogens during the layover. The immune boost was not connected to their fat levels, the team explained.

Researchers said that instead, the boosted immune systems arose from the much-needed rest from the strains of marathon migration, from factors such as the sheer physical exertion and then exposure to pathogens from new habitats.

“If you see a little bird in your garden or in the park during the autumn and you know that it is heading to southern Europe or Africa, it is fascinating to think about why it is taking a break,” said co-author Arne Hegemann in a news release. “If they do not get food or rest, their immune systems cannot recover, which is when they risk becoming ill.”