National Geographic’s Brilliant Beasts series has an excellent episode on Pigeon Genius. Watch it and you’ll be guaranteed to develop a new appreciation for these creatures, from slow motion footage of their impressive wing patterns (their wingtips actually touch at the top and bottom of their beats), to the still hotly-contested theories about how they maintain such remarkable homing navigation.
One of the more fascinating elements is how their strong monogamous bonds play into their homing instincts. A racing pigeon will be removed from its nest and partner for a few days prior to the race, then reintroduced to its beloved just before being taken away to race. This, in theory, gives it the maximum motivation to get home in a hurry.
Here's the first of four parts of the program; you can find all of them on Youtube.