Pigeons, in particular, are known for their innate homing ability, having been used as messengers since ancient times. We know that pigeons have some kind of internal magnetic compass, but exactly what it is and how it works has remained a mystery.

Now scientists are one step closer to decoding the birds' magnetic sense. Writing in the journal Science, Le-Qing Wu and J. David Dickman at Baylor College of Medicine described what happened when they put seven pigeons in an artificial magnetic field and observed their brains.

Wu and Dickman put the pigeons in a completely dark room, clamped their heads in place, connected their brain stems to electrodes, and used a Tesla coil to cancel out the effects of the Earth's magnetic field and to induce a new one. Then they fiddled with the angle and the intensity of the magnetic field and watched which parts of the pigeons' brains lit up.