Soaring over treetops and skyscrapers, you look out with a keen eye for potential mates and food, mindless of the intricate processes of flight. Your aerodynamic wings create mini-vortices that effortlessly push you aloft.
Your brain, too, is hardwired for flying down to your sensory systems: pigeons use built-in ferromagnets to detect their orientation with respect to the Earth's magnetic field. Like many species of birds, you detect compass directions during the daytime thanks to coordination between your biological clock and the daily movements of the sun.
With winter approaching you've been restless, receiving chemical orders to migrate to an environment richer in resources. These physiological processes in your body are responding to the changing day length. You will soon embark on a complex navigational adventure.
Some species of birds, like the Arctic tern, make a 25,000 mile round-trip journey every year. Others, like the short-tailed shearwater, circumnavigate an entire ocean to return precisely to the small island where they breed. Many experiments suggest that you possess an intricate olfactory map of areas surrounding your nest, and that common scents guide you home.