It is known that birds can sense the earth's magnetic field and use them to navigate  Recently, scientists in a country found that birds actually use their right eyes to view the earth's magnetic field  To test this theory, when birds began to migrate, scientists in the country put several Robin birds into a funnel-shaped and huge cage, and put a special metal eye mask that can shield the earth's magnetic field on one eye of some Robin birds  The walls of the cage are coated with marking substances  Birds can fly out only through the narrow mouth of the cage
The bird without eye mask and the bird with eye mask on the right eye flew out of the cage smoothly, and the bird with eye mask on the left eye flew in either direction
 If the bird touches the cage wall, it will stick a marker to judge whether the bird can find its direction