• Birds have substantial intrinsic, socioeconomic, and ecological value, making their conservation a priority. Socioeconomically, activities such as birdwatching and hunting support emotional wellbeing and contribute millions of dollars to the economy each year. Ecologically, birds offer vital services such as insect control, seed dispersal, and nutrient transfer. • The value of birds is reflected in state and federal laws, yet in North America, one third of bird species are at heightened risk of extinction. Climate change is widely considered a leading cause of declining bird populations. To mitigate the most severe climate change impacts on birds, greenhouse gas emissions need to be greatly reduced. Renewable energy sources, including offshore wind, can help achieve this. • Offshore wind energy offers economic, public health, and ecological benefits compared to other energy sources, including a pathway to meeting renewable energy goals, supporting energy independence, increasing grid stability, and reducing climate-driven threats to birds. Realizing these benefits responsibly, however, requires understanding how birds interact with offshore wind infrastructure and ensuring that projects avoid and mitigate potential harms so that the broader benefits of development outweigh its costs. For more detailed information and scientific citations, please see the full FAQ document linked below.

• Offshore wind facilities are typically comprised of turbines, whose rotors convert mechanical energy from wind into electrical energy, and offshore substations, which collect and modify energy from turbines for transmission. Energy is transported between substations and the shore via subsea power cables (which are typically buried in the seafloor) so it can be integrated into the electrical grid on land. • Turbines can have either fixed foundations installed on the seafloor, or floating foundations, which are anchored to the seafloor with specialized mooring lines. Floating turbine designs are newer and are generally deployed in deeper waters (50–300 m, or 164–984 ft). For more detailed information and scientific citations, please see the full FAQ document linked below.

• Birds use offshore environments for various activities such as foraging, resting, overwintering, and migrating. Seabirds can be found in offshore environments year-round, but the types, numbers, and densities of species vary seasonally and geographically. • Songbirds and other landbirds can occur in large numbers over the ocean, especially during migration. When, where, and at the altitudes traveled offshore varies by species. • When birds are offshore, their locations are behavior-specific and depend on multiple factors including transit to nesting sites during the breeding season. Seabird distributions are commonly driven by marine prey availability and local weather conditions. In contrast, landbirds and shorebirds that use offshore airspace primarily as a seasonal transit corridor, have distributions commonly driven by migration timing, the prevailing wind conditions, staging (migratory stopover), and overwintering locations. • Seasonal distribution models are available for 49 marine bird species in the U.S. Atlantic region, providing information about when and where birds are found. The distribution models indicate that the relative density of marine birds is highest near shore and decreases beyond approximately 10 km from land. For more detailed information and scientific citations, please see the full FAQ document linked below.

• Birds from a variety of taxonomic groups have the potential to be affected by offshore wind energy development. Reducing emissions that contribute to a warming climate via a renewable energy supply, such as offshore wind energy, could provide long-term benefits to hundreds of bird species in North America that are vulnerable to climate change. • Offshore wind energy development can also cause more immediate effects. Vulnerability analyses are studies that identify species at higher and lower risk from offshore wind energy development from an individual facility or across broader development regions. • Due to their extended presence in the marine environment, seabirds are more likely to interact with offshore wind facilities and to be affected in more ways than landbirds that migrate over the ocean occasionally. • Some bird species are attracted to offshore structures for perching and feeding opportunities, or because of attraction to artificial light. Seabirds such as gulls and cormorants are most frequently documented interacting with offshore wind facilities to date, due in part to the relative ease of monitoring these large-bodied species, as well as their degree of potential overlap in habitat use with areas of offshore wind energy development. • Some bird species avoid offshore wind turbines. Marine birds such as loons, sea ducks, and gannets generally avoid interacting with turbines which sometimes results in effective habitat loss, i.e., displacement. For more detailed information and scientific citations, please see the full FAQ document linked below.

• North American bird populations are in decline. Because major human impacts such as climate change and habitat loss occur on a broad scale, calculating the total bird mortality from these drivers is often challenging. Other sources of mortality include land-based collisions, fisheries bycatch, and invasive species. • On land, the leading cause of bird mortality is domestic cat predation (estimated to cause billions of annual mortalities in the United States alone). Collisions with buildings, automobiles, and power lines, as well as interactions with oil pits, each individually cause millions of annual bird mortalities. In comparison, collision mortality from land-based wind energy turbines in the U.S. is estimated to be in the hundreds of thousands. The top sources of mortality in seabirds are estimated to be fisheries bycatch, invasive species, and climate change. There is substantial uncertainty in most of these estimates, however. • Little is known about potential bird mortality from U.S. offshore wind energy development. This is due to the nascency of the industry (i.e., less time to collect data), the challenges of retrieving birds that collide with offshore infrastructure and fall into the ocean, and the uncertainty inherent in collision risk models. However, best-available scientific knowledge indicates that collision mortality from offshore wind energy turbines is relatively low. • Climate change is a leading cause of bird population declines globally. Thus, any realized bird mortality from offshore wind energy development needs to be considered along with the benefits to birds of renewable energy development when used to reduce emissions that cause climate change. For more detailed information and scientific citations, please see the full FAQ document linked below.

• Offshore wind energy development presents both benefits and risks for birds. The scale and duration of impacts can be evaluated to determine the tradeoffs. • Bird abundance has substantially declined over the last several decades and the most wide-scale threats to birds are driven by human activities and exacerbated by climate change. Offshore wind energy development aims to reduce carbon emissions that contribute to warming while still producing energy, with the potential benefit of mitigating climate change threats to birds globally. • Some birds may also benefit from new foraging and roosting opportunities offshore while others may experience localized negative effects such as displacement or rare collisions with turbines. • Current evidence suggests that the benefits of reducing the impacts of climate change can outweigh potential harms when offshore wind energy development projects are planned and managed with science-based decision making to avoid, mitigate, and compensate for negative impacts on birds. For more detailed information and scientific citations, please see the full FAQ document linked below.

• Most human development activities have some uncertainty regarding the degree of resulting environmental impacts. All types of energy generation have environmental consequences for birds and other wildlife. • There are many measures in place to protect birds, monitor their responses, and mitigate harm during the planning, construction, and operation of offshore wind facilities. • A broad range of ecological research studies designed to reduce uncertainty around potential impacts of offshore wind energy development are underway at sites in the U.S. and elsewhere around the world. • It is important to balance uncertainty around potential negative impacts with the predicted benefits of offshore wind energy development to mitigate global climate change, which is a leading cause of bird population declines, as well as with the comparative impacts from other energy development, especially fossil fuel extraction. For more detailed information and scientific citations, please see the full FAQ document linked below.