Avian Long-Distance Navigation: Experiments with Migratory Birds

Abstract

Many avian migrants perform the most impressive long-distance flights between breeding and wintering areas sometimes located several thousands of kilometres apart. These birds clearly have adapted to a mobile life style where fuel economy and navigation performance must have played a major role in the selection process shaping these extraordinary abilities. Perhaps one of the most fascinating capabilities is the solo migration flights by many young migratory songbirds, for which a complete migration program inherited from their parents is stored in their genes coding flight distance and direction, which enables the individual bird to fly completely alone from the site of birth to a sometimes very distant wintering area (for review see Berthold 1996). However, not less impressive is the ability possessed by many birds to relocate known sites of importance, like breeding sites, wintering territories and even stopover sites located between these areas (e.g. Mewaldt 1964; Per-deck 1967; Moreau 1972). Furthermore, each individual bird must possess the capability of performing a diverse array of behaviours to cope with navigational tasks over distances of a few meters up to several thousands of kilometres. For instance, most birds are central place foragers during the breeding period with short-distance movements within their home range. The functional characteristics of the navigational program and the cues that are of importance to locate known sites are, however, not very well known. In navigation studies of birds mainly homing pigeons, Columba livia, have been used for experimental convenience (for recent reviews see, for example, Papi 1982, 1991; Walcott 1996; Wallraff 1991, 2001), and much less effort have been invested in studying similar phenomena in migratory birds (e.g. Alerstam 1991; Berthold 1996; Matthews 1968; Wiltschko 1989). Therefore, detailed understanding of long-distance navigation in migratory birds is still very limited.