Check out this new paper by Paxton et al. on carry-over effects from winter to the migratory period. “We use a long-term dataset and provide strong evidence that not only is the stopover biology of migratory landbirds influenced by events during the previous phase of their life-cycle, but where migratory birds over-winter determines how vulnerable they are to global climatic cycles.”
El Niño-Southern Oscillation Is Linked to Decreased Energetic Condition in Long-Distance Migrants