Migratory birds like the European robin navigate using Earth's magnetic field by sensing its angle of inclination. According to the leading hypothesis, a retinal protein called cryptochrome reacts to light by forming pairs of molecules sensitive to magnetism, so the bird may 'see' magnetic north overlaid on its vision. Even weak electromagnetic noise can scramble its compass.
In 2022, a young tagged bar-tailed godwit flew from Alaska to Tasmania in about 11 days of nonstop flight, covering 13,560 km without eating, drinking or landing. Before departure, these birds pile on huge fat reserves and shrink their digestive organs, which are useless during the journey.
To escape rivals, a dung beetle rolls its ball of dung in a straight line. At night, it holds its course using the glowing band of the Milky Way. In a planetarium, researchers showed that beetles rolled straight under a starry sky but wandered aimlessly when the galaxy was switched off. It was the first animal known to navigate this way.