Scientists have known that birds can detect the Earth's magnetic fields since 1968, but a new study published in this month's issue of Current Biology asserts that birds can actually see them.
European robins were outfitted with "somewhat unflattering goggles" that helped researchers determine how the magnetic fields appear to the subjects.
The experiment showed that robins' sight of magnetic fields uses a molecule called cryptochrome found in avian retinas.
The cryptochrome molecule becomes active when struck by blue light, and that activity is picked up by the retina.
However, the robins' perception of magnetic fields is contingent on clear vision in the right eye. Researchers found that blurred goggles covering the right eye disrupted their ability.
- Robins can literally see magnetic fields, but only if their vision is sharp (Discover)
- Published study (Current Biology)