The Scottish Government has set a target of 100% of Scottish demand for electricity to be met by renewable sources by 2020. Offshore renewables have the potential to make a significant contribution to achieving this target. However, the Scottish Government has a duty to ensure that offshore renewable developments (ORDs) are achieved in a sustainable manner, by protecting habitats and species from adverse impacts. ORDs may negatively affect seabirds, in particular due to collisions with turbine blades, displacement to less favourable habitats and barrier effects to movement. Population Viability Analysis (PVA) is a common approach in Environmental Impact Assessments to forecast potential impacts of marine renewables on protected populations such as seabird species. There are several methods of PVA available to use that vary in their complexity, data requirements and biological reality. This project provides a comparative investigation of these methods for seabirds, describing model performance, providing a set of recommendations for practitioners and highlighting research gaps. The project recommends the use of the Leslie-matrix model as the most broadly applicable and biologically realistic method with the additional recommendation of adjusting demographic rates relative to abundance data, in those populations where adequate abundance data are available, to reduce uncertainty in forecasting. The report recommendations provides a roadmap for improving how PVA is used in environmental assessment providing practical approaches for practitioners of PVA. Specifically, these recommendations help work towards improved common approaches to predicting impacts and reducing uncertainty in assessments. This research is part of the Scottish Marine Energy Research Programme (ScotMER).