Biology
Magnetoreception and Geomagnetic Mapping in Migratory Songbirds
Quick fact
Migratory songbirds can sense the direction of Earth's magnetic field, and some species may even use a magnetic map to determine their position—a feat that relies on light-sensitive molecules in their eyes and tiny iron crystals in their beaks.
Why this is interesting
How does a tiny songbird find its way across thousands of miles, returning to the same backyard year after year? Some birds navigate using Earth's invisible magnetic field.