Some birds can sense Earth's magnetic field, using it to navigate. But precisely how they do this has long remained a mystery. Now, researchers have confirmed that a protein found in bird eyes - the cryptochrome - displays a quantum mechanical phenomenon which makes it sensitive to magnetic fields. The researchers suggest this mechanism could be behind birds’ magnetoreception abilities.Research paper: Magnetic sensitivity of cryptochrome 4 from a migratory songbirdNews and Views: Unravelling the enigma of bird magnetoreception