Wild seabirds that face high energy demands during the breeding season go on to migrate farther and raise more chicks the next year, but at a cost to their own survival. An international team, led by researchers from Nagoya University, raised the energy cost of flight for some birds and tracked them through the next year of their annual cycle. The researchers introduce a concept called "energetic flexibility" and offer rare experimental evidence for how the costs of one season carry over to shape the next. The study appears in Proceedings of the Royal Society B.