Biology
The Sensory Basis of Magnetoreception in Migratory Birds and Sea Turtles
Quick fact
A migrating robin can detect a change in Earth's magnetic field as small as a few dozen nanotesla—millions of times weaker than a refrigerator magnet—and use it to orient its flight.
Why this is interesting
Every year, arctic terns fly from pole to pole and sea turtles cross entire oceans—yet they never get lost. How do they know where to go?