Each fall a small group of bird biologists gather on Block Island, 13 miles south of Rhode Island, in Narragansett Bay. There they wait day after day for the raptors to come.
For about a century, ornithologists have known the importance of Block Island to songbirds. But until recently they hadn’t confirmed the ways in which migrating raptors—like merlins, peregrine falcons or American kestrels—use the island on their travels up and down the Atlantic coast, says Scott Comings, associate state director for The Nature Conservancy’s (TNC) work in Rhode Island. The Conservancy has protected about 46 percent of Block Island. Turns out, he says, “It’s sort of like a rest stop on I-95.”
In 2012, the Maine-based Biodiversity Research Institute (BRI) set out to learn more about raptors’ migrations up the Atlantic coast. For two years, they tracked raptors stopping on Block Island with help from a Department of Energy grant; the agency wanted information about the birds’ flyways as interest in offshore energy development grew. Beginning in 2014, TNC and the Bailey Wildlife Foundation began funding the work as the researchers tried to fill in data gaps on the ecology of migratory raptors’ stopovers, in which birds find shelter and food as they travel long distances.
“One of the reasons for that is that peregrine falcons are known to fly hundreds or more miles offshore,” says Chris DeSorbo, the raptor program director for BRI. Knowing where birds fly over the sea can help agencies make better decisions about where to allow offshore energy development.
Offshore wind is an ongoing conversation along much of the Atlantic Coast, making studying the effects on wildlife a key research question. Just last year, the nation’s first utility-scale offshore wind development began operating with five turbines off the coast of Rhode Island.
Bird banding has revealed a tremendous amount of information to ornithologists, but the mechanics of it mean that researchers have previously known where birds stop but not necessarily where they go in between rests. Satellite- and radar-tracking tools reveal so much more, and as transmitters have shrunk in size and weight over the years, smaller and smaller species have been studied with tracking devices.
“It’s allowing people to see amazing animals up close,” Comings says. “You’re seeing a window into their lives that you normally wouldn’t get.”
Each fall the team captures a variety of raptors—merlins, peregrine falcons, northern harriers, American kestrels. They take measurements and blood samples, band the legs of some of the birds and attach nanotranmitters or larger GPS trackers to others. Then they wait for the data come in, and they follow the lives of the individuals they met on the island.
“One male peregrine—instead of heading south, this one went due east about 1,000 miles offshore and then went another 400 to 600 miles south,” DeSorbo says. “It was hitchhiking on these offshore barges in the ocean.” Another peregrine he tracked in 2012 got caught in Hurricane Sandy as it flew south and the storm moved north.
The merlin tracking has revealed perhaps even more. “We learned more about merlin migration than has ever been known,” Comings says. “Where they’re going and how they’re going—it’s information that’s never been had.”
All of it, he says, helps conservationists make decisions about what areas to conserve next.
In October 2016, Washington, D.C.-based photographer Karine Aigner waited in bird blinds with the researchers, capturing images for a Nature Conservancy magazine story on different ways scientists use technology to track animals. For more animal tracking stories, read the full magazine story. Below, Aigner shares images of the tracking process on Block Island.