Animal navigation, long mysterious, may about to become better understood.
An unexpected mechanism in homing pigeons appears to sense magnetic fields and transmit the signal to the nervous system in ill defined way.
Ferritin containing macrophages were found in the liver near nerve cells which might transmit signals to the brain. Ferritin is a form of iron used to move it around in animal bodies in a controlled manner. The macrophages presumably get the ferritin when recycling old blood cell...