Wind energy is the fastest growing source of electricity in the U. S., and the energy potential in the offshore environment is enormous. Environmental concerns have focused on effects on birds, and in this paper we briefly review these effects in the context of methods for assessing preconstruction risk and post-construction impact. Federal statutes and legislation, including the National Environmental Policy Act, Federal Energy Act of 2005, the Endangered Species Act, and the Migratory Bird Treaty will require that prospective developers conduct some form of avian risk assessment prior to construction. Such preconstruction studies should utilize a Before-After-Control-Impact (BACI) design.
Offshore wind farms pose three primary threats to birds: barrier effects due to flight avoidance, habitat loss (due to displacement), and fatalities resulting from collisions with turbine blades. All have been demonstrated at land-based and coastal wind farms, and flight avoidance and shifts in habitat use have been demonstrated in the offshore environment for a limited number of species in Europe. The additive effect of these impacts to bird populations may be trivial under current levels of development, but could become ecologically significant as offshore installations increase as projected.
Interpreting the ecological significance of these effects requires additional research, especially on understanding the importance of winter foraging habitat and population delineation, particularly for waterfowl. Such research and preconstruction studies will be expensive, and we suggest public funding of these efforts and private-public partnerships as is currently underway in some states.