GPS tags mapped 17 woodcock crossings over the Gulf of Maine and revealed three invisible routes, with four flights reaching future turbine-blade height even though more than 88% of the birds would miss the wind sites entirely

The sky above the Gulf of Maine gets busy in autumn. Dozens of American woodcocks that spend the warmer months feeding in the north migrate to the southern and southeastern regions for winter. 

Avian researchers fitted some of these birds with miniature GPS tags to track their risky open-water flights and compare their paths to designated wind farming zones.

Most migration corridors bypassed these areas, but three distinct “highways” over the ocean were observed. How were these three routes created?

How open-water migration movement is tracked in the gulf

The thickets, forests, and pastures of eastern North America are home to ground-dwelling American woodcocks in spring and summer. In the fall, they head from eastern Canada and New England to winter in Louisiana, Mississippi, Alabama, Georgia, Florida, the Carolinas, and eastern Texas. But before reaching the warmer locations, they have to make a taxing trip over the expansive Gulf of Maine.

Some birds take long detours around the coast, using up more energy to fly further for longer. Others head straight across the water, making the trip in the dark.

Researchers tracking these nighttime journeys with lightweight satellite GPS transmitters noted 17 open-water crossings across multiple migration seasons. They confirmed that the woodcocks regularly make offshore flights, with some crossing tens of miles, according to the Nova Scotia Federation of Agriculture.

Vast sections of the Gulf of Maine have been earmarked for future offshore wind energy projects, and conservationists need to know where migration routes and turbines might overlap. 

Flight paths and altitude vs. energy infrastructure risk

Evaluating the risk that wind turbines might pose to migrating birds involved tracking both their flight paths and altitude profiles. 

Modern offshore turbines have blades 300 to 400 feet long, reaching hundreds of feet into the air. These are serious collision hazards for birds choosing to enter that airspace. 

The tracking data showed that woodcocks followed distinct channels across the sea rather than taking random routes to get across the gulf. 

The birds stayed surprisingly low, with four of the recorded crossings ending up in turbine altitude range. But spatial analysis revealed that around 88 percent of the flight paths avoided the proposed wind lease areas completely. 

Conservationists now have a baseline to work from, but they still need to understand the forces behind the distinct channels of migration. The factors that influence flight corridors are important to figure out if changing turbine boundaries could disrupt long-established routes. 

Wind patterns and departure geography shape three corridors

Three invisible corridors formed where coastal departure points met prevailing atmospheric winds during autumn cold fronts.

Researchers identified three main pathways: a northern route running from Nova Scotia straight to mid-coast Maine, a central route crossing the open gulf from Nova Scotia to Cape Cod, and a western coastal route stretching from southern Maine across Massachusetts Bay.

Favorable northwesterly tailwinds provide the necessary push for these journeys, guiding woodcocks along predictable atmospheric tracks that minimize energy loss over open water.

These wind-driven corridors naturally steer more than 88 percent of tracked woodcocks away from current offshore wind leases. Still, researchers emphasize that dataset limits apply, with only 17 recorded transit events so far.

Energy expansion and weather could change the situation entirely

Expanding lease zones or shifting weather patterns could change those exposure numbers in future seasons.

The tracking data shows that woodcocks rely on specific weather windows to cross maritime barriers, demonstrating how atmospheric currents build distinct migratory highways. Mapping these airborne corridors gives energy planners solid data to place offshore infrastructure where collision risks stay lowest.

A similar tracking project is currently examining how migrating ducks and geese react to new floating solar arrays in their flight paths.

You can find all the details in the full study here: Brunettea, C. S., Filkinsc, K., Rotha, A., McWilliamsb, S., Straubc, J., & Blomberga, E. (2026). AMERICAN WOODCOCK (SCOLOPAX MINOR) ECOLOGY IN EASTERN NORTH AMERICA–2025 Annual Report.