Oil spills are well-known for causing acute mortality of birds, but sublethal and delayed impacts are less understood. Focusing on the mallard ( Anas platyrhynchos ), we used simulation modeling to explore how sublethal oiling may affect avian survival and breeding ground body condition. We used empirically informed migration and energetics simulations to model hypothetical spills occurring in northern Arkansas, USA occurring in either January to simulate thermoregulatory stress or March to simu