"Predicting the impact of future climate changes on populations and biodiversity is of key importance in the connection with the current global warming. It is crucial to understand how organisms are able to cope with climatic variations, especially in polar environments where the effect of climate change is the strongest. Climate changes may have important ecological consequences on the population dynamics on the long-lived organisms. Because they are typically the upper trophic-level predators of a food chain, they might amplify the effects of climatic forcing on lower trophic-levels. These sensitive indicators of food-web changes are also suitable to study how effects of climate change may be mitigated by behavioural plasticity and evolutionary changes. In addition to the major role of their oceanic circulations in global climate, polar areas are of a particular interest because they hold some of the major animal biomasses of our planet. Resource abundance and availability in polar oceans might vary strongly between years, with effects on animal foraging efficiency, and consequently on demographic traits and the population growth rate. During this Marie Curie project, I will study the links between long-term population time-series on top-predators (seabirds) and environmental data (local and global indices). The analyses will be based on two different polar marine ecosystems: Southern Ocean and Barents Sea. Working with the state-of-the-art statistical tools used at the Centre for Ecological and Evolutionary Synthesis, centre of excellence at the University of Oslo, will allow me to investigate how seabirds adapt their demographic strategies depending on climate changes and their experience, and to predict how their populations will adapt to climate and oceanographic changes. Understanding the processes underlying population changes is essential for predicting the dynamics of the polar ecosystems, and hence to develop proper conservation measures of these systems."