A significant concern in the development of offshore wind farms is their potentially negative effect on birds. The general public’s perception of these effects does not always agree with the scientific evidence, however. To bridge this information gap, this study seeks to review and analyze the existing literature on birdwind interactions in order to assess what we know and to recommend mitigation solutions. The findings are then used to examine the impacts of a proposed offshore wind farm south of Cape Cod, Massachusetts. Much of our knowledge of avian effects at offshore wind farms comes from one site in Denmark, which demonstrated a disturbance effect on sea ducks caused by turbines, resulting in minor indirect habitat loss and a barrier to movement. Collisions with turbines remain the largest potential threat to birds from any wind farm, however, and evidence from extensive work at onshore sites has demonstrated that collisions will occur no matter where a farm is located. The magnitude and severity of all impacts, not just collisions, could best be minimized by the careful siting of proposed wind farms, although there are several other effective ways to mitigate impacts through design and planning. The proposed wind farm south of Cape Cod puts multiple groups of birds—passerine and seabird, migrant and local—at risk of collisions and other impacts. One species of primary concern is the federally-endangered roseate tern (Sterna dougalli), which has a large breeding and pre-migratory staging population near the proposed wind farm. In addition to requiring thorough pre- and post-construction avian monitoring regimes, U.S. policymakers should address our lack of offshore experience by limiting the size and scale of proposed projects until impacts on birds are better understood.