Birds have substantial intrinsic, socioeconomic, and ecological value making their conservation a priority. Socioeconomically, bird-related 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 risk of extinction. Climate change is widely considered a leading cause of declining bird populations. To avoid the most catastrophic climate impacts, 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, 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 density of species vary seasonally and geographically. Songbirds and other primarily terrestrial species can occur in large numbers over the ocean, especially during migration. When, where, and at what altitudes these birds fly offshore varies by species. When birds are offshore, their locations are behavior-specific and depend on multiple factors. Seabird distributions are driven in part by their nesting locations (in breeding season) as well as by prey availability and distribution. Migrating shorebirds and songbirds are more influenced by weather and staging (migratory stopover), breeding, and overwintering locations. Seasonal distribution models are available for 49 marine bird species, providing information about when and where birds are found in the U.S. Atlantic region. The distribution models indicate that the relative density of marine birds is highest nearshore and decreases beyond approximately 10 km from land. For more detailed information and scientific citations, please see the full FAQ document linked below.

Potential effects on birds from offshore wind are evaluated based on a combination of exposure (e.g., overlap in space/time between birds and wind facilities), effectors (the threat[s] posed by the wind facility), and vulnerability (e.g., how susceptible an individual bird or the bird species is to the threat). All three factors contribute to overall risk. Attributes of individual offshore wind facilities (including the physical presence of structures, associated lighting, and vessel traffic) can change habitat, resources, and foraging conditions. These shifts may exert positive, neutral, or negative effects on the surrounding ecosystem, and effects may change over the construction and operational periods of an offshore wind facility. Various bird life history characteristics such as flight height, body size, flexibility of habitat use, and migration strategy factor into the potential level of risk posed by offshore wind development across individuals, populations, and species. For more detailed information and scientific citations, please see the full FAQ document linked below.

There are many human-related sources of bird mortality that are broad in scope and challenging to measure, including climate change and habitat loss. Other sources of direct mortality include collisions, fisheries bycatch, and invasive species, which, in some cases, can be measured more easily. The scale of bird mortalities in the U.S. varies by source. On land, the leading direct cause of bird mortality is domestic cat predation (billions of annual mortalities). Collisions with buildings, automobiles, and power lines, along with interactions with oil pits, each additionally cause millions of annual bird mortalities. Seabirds also face many threats, with fisheries bycatch, invasive species, and climate change as top sources of mortality. Much less is known about potential bird mortality from U.S. offshore wind development, given the nascency of the industry and the difficulty of counting birds that collide with offshore infrastructure and fall into the ocean. European models for the heavily developed North Sea estimate bird collisions in the tens of thousands per year for planned 2030 buildout of this region. However, there is a great deal of uncertainty in these modeled estimates and offshore wind turbine collisions are thought to be much rarer than at land-based wind facilities. Bird mortality from offshore wind development needs to be balanced with the benefits of renewable energy in reducing climate change, as climate change is a leading cause of bird population declines globally. For more detailed information and scientific citations, please see the full FAQ document linked below.

Collaborative research efforts like Project Wildlife and Offshore Wind (WOW) bring together cross-sector expertise and resources to address research questions about potential effects of regional offshore wind development on marine wildlife, including seabirds. Organizations also invest in developing, testing, and validating new technologies to monitor bird interactions at and around offshore wind facilities. Through specialist working groups and committees like the Offshore Wind Environmental Technical Working Group, organizations share knowledge and engage with each other to identify research priorities and to develop guidance, products, and studies that address knowledge gaps about bird interactions with offshore wind development. Conferences and workshops like State of the Science on Offshore Energy, Wildlife, and Fisheries and the Conference on Wind Energy and Wildlife Impacts facilitate cross-sector knowledge exchange and engagement among government agencies, the scientific community, conservation groups, and offshore wind developers to share research findings and identify data gaps. Many offshore wind developers are also voluntarily committed to achieving net positive impacts. For example, developers conduct conservation or restoration efforts that generate greater ecological benefits than negative environmental effects related to their offshore wind project(s). For more detailed information and scientific citations, please see the full FAQ document linked below.