Birds are some of the most wide-ranging species on the planet, with many navigating with unerring accuracy. They are also ecologically diverse, making birds a promising model for functional studies of navigation. Despite this, most research on avian navigation has focused on the mechanistic basis of navigation, particularly which sensory cues birds use. In this chapter, avian navigation is placed in a functional context. Issues that navigating birds face and resolve are outlined, including navigation at different scales, variation in environmental information, how conflicting information is managed, detouring around ecological barriers, and navigation through wind. These five areas highlight the potential of a systematic cognitive ecology of avian navigation, placing navigation by birds and other taxa in a comparative, ecological framework. To guide future work, open questions regarding the problems that birds face, and the solutions they have evolved, are presented to facilitate such an ecological approach.