Disrupt is 5-year project (2020-2025) funded by the Academy of Finland. Migratory waterbird populations have dramatically declined worldwide. In parallel, the proportion of females has considerably decreased in these populations. Increasing predation of incubating females has been put forward to explain such declines. However, the range of species affected by sex ratio bias towards males and the spatial scale of the processes suggest that other factors are involved. The increase of pollutants in the environment may contribute to these declines via a reduction of fertility, or an alteration of the immune response, especially of females. In birds, egg production and viability, as well as sex differentiation and the immune response involve hormonal mechanisms that can be altered by pollutants. Among them, endocrine disrupting chemicals (or EDCs) are of particular concern. We are studying EDCs exposure and their biological effects in waterbirds, with special focus on: the common Eider Somateria mollissima and the Common Goldeneye Bucephala clangula
