Magnetic Orientation and Celestial Cues in Migratory Orientation

Abstract

Young birds on their first migration possess innate information on the direction of their migration route. It is represented twice, using both celestial rotation and the geomagnetic field as references. These two systems, together with information provided by factors associated with sunset, interact in a complex way to establish the migratory direction. During ontogeny, celestial rotation appears to be dominant; during migration, however, celestial cues appear to be controlled by the magnetic field. -The factors associated with sunset -the view of the setting sun and the characteristic pattern of polarized light -are important secondary cues which seem to derive their directional significance from the magnetic field. Their role appears to be more variable, with possible species-specific differences.During spring migration and later autumn migrations, flying in the migratory direction is complemented by navigational processes which enable the birds to return to a specific home site known from previous stays.

Navigation and seasonal migratory orientation in juvenile sea turtles

“…The orientation behavior of the turtles during the migratory season closely parallels the restlessness exhibited by captive, migratory birds (Wiltschko and Wiltschko, 1991). Avian researchers have been able to exploit this behavior to investigate a number of factors related to bird migration, including the cues used to orient and navigate (Munro et al, 1997;Wiltschko et al, 1998), the genetic basis of migratory orientation (Helbig, 1996;Pulido et al, 2001) and the circannual rhythms involved in migration (Gwinner, 1996).…”

A Mathematical Expectation Model for Bird Navigation based on the Clock-and-Compass Strategy

“…To cope with the tasks of migration, it is well established that night-migrating passerines have an inherent time schedule (for a review see Berthold, 1991;Gwinner, 1996), and at least two compasses, a magnetic compass and a celestial compass (e.g. Alerstam, 1990;Wiltschko & Wiltschko, 1991Mouritsen, 1998). Furthermore, at least an initial migratory direction is inherited (for a review see Helbig, 1996).…”

Homing of Cory's shearwaters (Calonectris diomedea)carrying magnets

“…The mechanisms underlying these performances are unknown, but results obtained with other birds suggest that sensitivity to the earth's magnetic field might be involved. Migratory passerine birds use the magnetic field to orientate their escape attempts from cages or funnels (Wiltschko & Wiltschko, 1990, and references therein), while homing pigeons carrying magnets are reported to be disorientated under overcast skies, at least in some experimental series (Keeton, 1971;Ioale, 1984;Moore, 1988). In general terms, birds are believed to rely on the magnetic field for direction finding, whereas it is very doubtful whether they use it to fix their position with respect to a goal (Wiltschko & Wiltschko, 1988).…”