Unhatched birds warn others by vibrating their shells

Baby seabirds can communicate with their brothers and sisters before they've even hatched, scientists have discovered.

They are able to warn their siblings about threats from predators by vibrating in their shells.

Scientists say these findings are important because being aware of and highlighting danger helps chicks adapt to life on the outside.

It improves their chances of survival in dangerous environments.

The research was done by the Animal Ecology Group at the University of Vigo, Spain.

They studied 90 yellow-legged gull eggs from Sálvora Island in Northern Spain.

The scientists found that the unhatched chicks responded to the external alarm calls by vibrating more and vocalising less.

However, they're still unsure how the chicks process and understand these vibrations as signals.