The aim of the project is to test for carry-over effects between geographically disparate regions in long-distance migrants. Specifically, we will study how decisions and experiences in one season impact a bird’s condition, behaviour and its success during subsequent seasons. We will take full advantage of recently developed miniature light-level geolocators that will provide detailed information about the location of wintering sites as well as the timing, direction and duration of migration. This geographic information coupled with local meteorological and productivity data, blood parasite loads and stable isotope measurements of winter-grown tissues will allow us to investigate consequences of wintering habitat quality for the subsequent migration and reproductive performance. We will also test whether reproductive effort and brood parasitism have downstream consequences for later stages of the annual cycle. The project will significantly increase our biological understanding of ecology and evolution of long-distance migrants and will be an invaluable asset to their conservation.