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Billions of organisms, ranging from bats to butterflies andwhales to wildebeest, engage in repeated movements between seasonally favorable environments. These move-ments vary from distances of a few to thousands of kilome-ters. Many birds, for example, spend more than half of each year in equatorial regions, and then fly great distances to breed in temperate locations. Others move even farther, leaving their temperate northern breeding range as winter approaches and traveling to temperate habitats in the Southern Hemisphere, as spring arrives there. Yet, despite the enormous number of individuals involved in such migrations, there are large gaps in our understanding of many aspects of migration. Even basic information, such as locations where individual organisms choose to breed and overwinter, remains rare and elusive. Acquisition and inte-gration of knowledge gained as a result of technologica