Publisher Summary This chapter describes the navigation system of birds. Because of their ability to fly, birds can move faster than animals, and this ability affects almost all aspects of their life. Rapid changes in location do not pose any threat. The distances normally covered by birds every day within their home range also exceed those of animals. Their home ranges are considerably larger than those of mammals of comparable size. The sun compass, as well as the “mosaic map” and the “grid map” form essential parts of the avian navigational system, but these mechanisms cannot be based on innate information since they make use of factors whose existence is reliable but specific manifestation cannot be anticipated. It is absolutely certain that birds will see the sun and will encounter landmarks and suitable factors to be incorporated into the “maps.” However, neither the local arc of the sun, nor the specific nature and position of landmarks, nor the regional distribution of gradients can be predicted. To make use of these factors, animals have to obtain relevant information through individual experience.