Sandpiper eggs in a nest. (Credit: Drakuliren/Shutterstock)

The speckled brown eggs of seabirds may look like lifeless lumps of shell, but inside, developing chicks are already paying attention to their parents. Researchers studying yellow-legged gull chicks have discovered that the animals can respond to their parents’ alarm calls while in the egg and even pass on the information to younger nestmates by rattling their shells.

The discovery shows that “even before hatching, embryos can u