In the pigeon's upper beak, there is a unit cell that can sense the magnetic field. This unit cell is a crystal structure, similar to magnetite. Pigeons grow up in one place and will adapt to the magnetic field. In the memory of pigeons, this magnetic field is a specific coordinate with our latitude and longitude. Pigeons will remember this coordinate no matter how far they fly. With magnetic navigation, pigeons can always fly home from thousands of kilometers away.
2. navigate by the sun.
In fact, there are other reasons besides magnetic induction. Pigeons are homesick animals, and once they leave their nests, they will feel uneasy. Pigeons are gentle, so they are timid and don't like to stay in strange places. So pigeons always have a strong desire to go home after flying out. Pigeons usually don't fly too far, but wander around their nests. In addition, biologists have found that pigeons can tell their directions by the sun. Pigeons will form a fixed biological clock and tell the direction once. So pigeons may get lost in a thunderstorm, because the sun and magnetic field are useless.