Released hundreds of miles from home, a pigeon still finds its way back

Homing pigeons released far from their loft, even somewhere they've never been, can navigate home with striking accuracy, apparently combining a magnetic sense with a mental map built from smells, sounds and the position of the sun. Decades of experiments, including fitting pigeons with magnets or frosted contact lenses, still haven't fully settled which cues matter most or how the birds weigh them against each other.

— Hans G. Wallraff, Pigeon Navigation — Animal Behaviour, review literature, 2001