Birds seem to know exactly where they are going when they are flying. It is almost as if they have their own flight plan. Have you ever wondered how birds have been able to stay on course without any complex equipment and technology that we have available?
For a while it has been theorized that birds and other animals, use the earth’s magnetic field to navigate. But it could never be proven – until now. Scientists have been able to show through various experiments that this is quite possible. Research has shown how a synthesized molecule can act as a magnetic compass. When exposed to light, the chemical forms a short-lived charge. This is similar to Earth's magnetic field.
How does this relate to birds? By being able to replicate how a molecule, when illuminated, can be affected by a magnetic field proves the theory that even in a magnetic fields as small as the earth’s, it can be used for navigation in birds and other animals.
Scientists have even further theorized that birds can “see” the magnetic field. Something called Crypto chromes have been found in the retinas of migratory birds. This molecule found in the visual system would suggest that birds could translate magnetic compass information into visual patterns. This along with light and a bird’s inner compass, allow the birds to use their visual system to reference direction much like a compass and see the magnetic field.
Also, some birds that fly at night have even been found to possess a night vision brain area. Researchers compared night migratory birds species to non-migratory species. They found that the night migratory birds showed high activity in the visual pathway under the moonlight compared to the non-migratory birds. They also found that this decreased during daylight.
Migratory birds calibrate their magnetic compass based on certain light patterns. These polarized light patterns are strongest at sunrise and sunset. With this guidance birds are able to set their compass and determine their flight plan.
The experiments conducted also confirmed that if birds do use the magnetic field, that man-made magnetic fields like power lines and communication equipment could disrupt the birds’ orientation. In fact, it did disrupt the orientation in European Robins.
This is only the beginning of research on this subject. Much more is needed to gain a better understanding of how this all works. But it certainly is an interesting start.