Despite having brains the size of peas, many birds are able to successfully migrate over long distances year after year. Their routes and beginning and end points are the same each year, ensuring the survival of the species if, for example, the migration is between spring breeding grounds and a place where there is food in the winter. Some birds, like the Bar-tailed Godwit, fly non-stop over oceans for over a week and end up in the right place. That birds can do this while many humans need to rely on their GPS to get to the corner store is one of life's great mysteries.
A few heroes in Godville, whose brains are probably slightly larger than peas, have learned the secret of bird migration and called it, unimaginatively the "Flying Bird" skill. This skill reduces the travel time when returning to a town. Once he or she leaves town with a lighter bag, lighter coin purse, and likely, lightheaded, the skill also reduces the travel time to return to the furthest milestone he or she reached before turning around.