Migration represents one of the most complex and fascinating behaviours in nature. Found in a wide variety of taxa including insects, fish, reptiles, mammals, and birds, migration can span thousands of kilometres and occur over multiple life-history stages and habitats. Identifying the factors that influence individual success and population abundance requires knowledge of how events are linked throughout the migratory cycle. The primary obstacle, thus far, has been the inability to track individuals over large geographic distances, resulting in research that has been limited to isolated stages of the migratory cycle. This has made it challenging to determine how populations are spatially connected between periods and for understanding how events in one season carry-over to influence success in subsequent seasons. Novel technologies, such as stable isotopes, trace elements and radio-telemetry are beginning to bridge these gaps by providing the ability to integrate life-history and demographic information throughout the migratory cycle. The long term goals of my research are: (1) understand how events within and between seasons interact with behaviour and habitat quality to influence population abundance and life-histories, and (2) parameterize and develop a set of predictive models that can be used to test aspects of life-history evolution and population dynamics in migratory animals, (3) develop and refine sets of accurate and non-invasive methods to track individuals over large geographic distances, and finally (4) apply year-round populations models to construct optimal conservation plans that can be used for a variety of species worldwide.