The Mediterranean Stopover Ecology

The Mediterranean stopover ecology in the orientation and navigation context.

Migratory birds face navigation and orientation challenges. This paper explains how, in order to face those challenges, they are equipped with an inherited route direction and distance information and with an ability to calibrate it with environmental cues, such as geomagnetism, celestial rotation, the sun and polarized light, wind, odors, landmarks, and visual and vocal contact with their co-species. It examines how the variability in the characteristics of these cues over time and in respect to the geographic position of the bird during the migration can result in disorientation, navigational errors, and a consequence disposition. It examines the stopover sites in the Mediterranean basin, which, besides being important refueling stations for migratory birds, have also the capacity for serving as a multi-cued reorientation sites that facilitate landmark, visual, vocal, and even olfactory navigation. These sites in general, and Eilat in particular, can study the target sites of numerous species by combining direction studies with distance studies migratory species and thus set the stage for future navigation-related studies.
“Migratory birds seek to exploit temporal food resources in different parts of the globe in winter, and to come back to the breeding grounds in spring (Terril, 1991). In order to successfully reach that goal, birds must not only correlate their migration phenology with ecological dynamics at the destination, but must rely on an efficient, calibrated and accurate navigation system, coupled with a strong sense of orientation (Wallraff, 1991). Migration under poor navigational ability and/or orientation mistakes can result both in arriving to unsuitable habitats and in unsuitable arrival timing (Busse, 1992). Such errors force migratory birds to reorient and reroute their direction, a process that is not only time consuming, but also results in the elongation of the initial route by up to twice the original distance (Busse, 1992).”

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