Migrating birds may break for immune system boost

Researchers knew migrating birds made stopovers to refuel. But a recent study suggest they also take a break to boost their immune systems.

“This is the first time that this has been demonstrated in wild migratory birds,” said Arne Hegemann, a biologist at Sweden’s Lund University who led the research published in Biology Letters.

Migrating birds regularly stop in one place for a few days to rest and eat. This was previously thought necessary to build up new fat reserves. But after collecting and comparing data from different individuals and species, Hegemann’s team found they also build up their immune system during these stops. The team examined examined small migratory birds—such as chaffinches (Fringilla coelebs), dunnocks (Prunella modularis) and common redstarts (Phoenicurus phoenicurus)—and analyzed how their immune system changed when they took a break during migration.

“This provides an important part of the puzzle of how migratory birds cope with the physiological challenges they are faced with on their long journeys,” Hegemann said.

Read more from Lund University.