They are born with a natural instinct that enables them to navigate their way home.
Pigeons are doves.
Doves are pigeons. The racing homer we see today is descended from the rock dove. This beautiful athlete in the sky has come about through man's intervention using selective breeding over many thousands of years. One should be aware to never use the small white ring neck dove, as these birds have neither the ability, strength or insticts to find their way home. They will be a great disappointment to anyone that releases them, for all they will do is fly to the ground or the nearest tree, and in a matter of days will perish.