THE STUDY OF BIRD MIGRATION BY RADAR .1. THE TECHNICAL BASIS

Since the 1960s radar has been an established research tool in bird mi gration studies. Radar informs us about the actual course of migration under various environmental conditions: it covers wide distances, is independent of light and reasonably independent of weather, provides d ata on migratory intensity, flight paths and with special equipment th e wing-beat pattern of birds. It thus fills an important gap left by o ther methods such as visual and auditory observations, laboratory rese arch, trapping, and ringing studies. For an appropriate use of the sop histicated tool, however, it is important to know its capabilities and limitations.