ABSTRACT
It is well known by biologists, paraprofessionals and lay persons that many birds and a variety of other vertebrates (e.g., fishes, marine mammals) migrate annually. This means that these species make an annual round trip between their breeding and nonbreeding ranges. In many instances the distances traversed can be measured in thousands of kilometers and the goals at each end of the migration route frequently are precise, with individual birds, for example, returning to the same hectare of habitat year after year. Numerous studies involving marked animals, either banded or otherwise individually recognizable, have documented the distances traveled, the seasonal ranges of particular species and individuals, and the seasonal periodicity of such movements (1, 2). The migratory ability of birds and the associated direction-finding methodologies have been studied more thoroughly than similar behavior in other vertebrates. Most of this review, therefore, will be devoted to the state of our knowledge about avian orientation and navigation.
