ORIENTATION AND NAVIGATION OF MIGRATING BIRDS

The question of how migrating birds find their way towards wintering areas and back fascinates researchers since the beginning of scientific studying the avian biology. Migrating birds are shown to possess a compass system, which allows them to select and maintain certain compass directions. Three such systems, as solar, stellar and magnetic ones, are known. Their details are not quite clear and need further research. The hierarchy and interaction of compass systems in migrating birds have been poorly studied; different species may vary in this respect. During migration, birds learn to use maps that make possible true navigation, i.e. to detect the position towards the goal of movement. The physical nature of navigational maps is an object of intensive research; currently, the most promising concepts are geomagnetic and possibly olfactory maps. A significant contribution to the formation of navigational maps was made by Soviet/Russian researchers, whose work was published in Zoologicheskii Zhurnal (Sokolov et al., 1984). Migrating birds have no innate map, and first autumn individuals reach their species-specific wintering areas by using a compass sense and counting the time that should be spent for moving in certain genetically fixed directions. However, in the recent years, more and more data suggest that juveniles (maybe not of all species) do have some mechanism of controlling their position on the migratory route that allows them to compensate for errors of the spatial-temporal program of migration.