Satellite Tracking Highlights Use of Ocean Habitat by Diving Bird Species in Federal Waters of the US Mid-Atlantic

Offshore wind energy is one of the fastest-growing sectors of world energy development, offering a clean abundant source of electricity to meet demands. Offshore wind facilities may however impact many bird species, exposing... [ view full abstract ]

Offshore wind energy is one of the fastest-growing sectors of world energy development, offering a clean abundant source of electricity to meet demands. Offshore wind facilities may however impact many bird species, exposing them to increased mortality through turbine collisions, and by altering behavior and flight pathways. Several wind energy facilities are currently being planned for offshore U.S. Atlantic waters. To evaluate the potential for effects on marine birds posed by wind turbines in Federal waters (>5.6 km from shore), there is a need to collect information on the distribution, seasonal occupancy and behavior (e.g., flight pathways timing, etc.) of a broad suite of birds in these areas. Our project evaluated the fine-scale occurrence and movement patterns of three diving bird species with different flight and foraging characteristics in the near-coastal federal waters of the U.S. mid-Atlantic area (North Carolina to Long Island, New York). From 2012-2016, we tracked the movements of Northern Gannets (n=75) and Red-throated Loons (n=66), and from 2001-2016, Surf Scoters (n=217) in mid-Atlantic waters, on their northward migration to their breeding colonies, and on their southward migration back to and through the mid-Atlantic region. The mid-Atlantic region and the Gulf of Mexico are hotspots for Northern Gannets during winter. Different age classes of gannets from colonies in both major breeding areas (Gulf of St. Lawrence and eastern Newfoundland) use estuarine, bay, coastal, and pelagic habitats during winter. During the return fall migration, both colony and winter-caught gannets move from shelf to coastal waters, as they travel to or pass through the mid-Atlantic region on their way to the South Atlantic Bight or Gulf of Mexico. The use of coastal waters appears to be more pronounced among females. Red-throated Loons’ winter use near potential wind energy lease areas was greatest along the western edge of the North Carolina wind-planning area off the Outer Banks; spring and fall migration movements also overlapped with that area. Migration trajectories through New Jersey and Delaware lease blocks were heavier during the spring than fall. In general, the greatest chance for interaction between Red-throated Loons and potential wind energy areas occurred during the migration periods rather than winter. Kernel density estimations for both sexes of Surf Scoters showed that core-use areas during the wintering period encompassed the majority of both Chesapeake Bay and Delaware Bay, with additional smaller core-use areas occurring south of Cape Cod near Nantucket Shoals, in Long Island Sound, and in Pamlico Sound, NC. During migration scoters followed a route within 18.5 km of the Atlantic coastline to staging areas near the Gulf of St. Lawrence, therefore, may not be influenced by the proposed wind energy areas controlled under Bureau of Ocean and Energy Management (BOEM) jurisdiction, but state plans may impact this species. Data are designed to inform permitting and regulation of future offshore wind development in the Atlantic region and provide important information on key habitat use and migration of a suite of species with different ecological niches.