How Migrants Get There: Migratory Performance and Orientation

Migratory animals show a suite of adaptations to cope with their journeys. These include not only morphological features for efficient locomotion and storage of energy but also behavioral adjustments to exploit winds and currents or to avoid drift caused by moving fluids. Migration strategies across locomotory modes can be analyzed in the context of optimality models, using some general principles concerning migration range and selection criteria. Comparisons of model predictions with natural behavior help researchers understand the selection pressures that underlie migration strategies. We give examples of typical migration speeds and distances for animals using different locomotion models. Successful migration also requires accurate orientation and/or navigation between distant areas for reproduction and survival. Animals can use a suite of different compasses, which may be cross-calibrated or integrated for direction finding, depending on the geographical and ecological situation, and may be used with an endogenous clock for time compensation.