Each year, billions of birds migrate thousands of miles with astonishing accuracy—often returning to the same tree or nest year after year. But how do they do it? Research suggests birds rely on a multi-layered navigation system that includes the sun, stars, Earth’s magnetic field, and even smells.
One of the most mind-blowing discoveries is that some birds might actually “see” the Earth’s magnetic field using a special protein in their eyes called cryptochrome. This helps them perceive magnetic fields as visual patterns—a sort of built-in compass overlaying the world around them. Combined with other cues, this system allows birds to traverse continents, oceans, and even deserts—no GPS required.