Home - Songbird Superhighway – Spring 2011
In addition to the groundbreaking nature of the findings and combination of research methods, the collaborative nature of the Network itself is unheard of in the world of bird migration research, at least in the Gulf of Maine.
Faculty and student researchers from UMaine and Acadia University in Nova Scotia are involved, along with U.S. Fish & Wildlife Service biologists at the Maine Coastal Islands National Wildlife Refuge, the National Park Service and several established bird banding stations such as the Atlantic Bird Observatory in Nova Scotia, Appledore Island Migration Station in the Isle of Shoals, and Manomet Bird Observatory in Massachusetts.
Network researchers are now collecting data about the species and numbers of birds captured on the migration highway, as well as where they come from and where they’re going. The Network’s ultimate goal, however, isn’t to simply amass information. Scientists are hoping to have as clear of an understanding as possible about the gulf’s migrants because current and emerging issues such as climate change, loss of habitat through development of inland and coastal areas, and alternative energy initiatives along the Maine coast will inevitably affect the mass migrations.
“We’re at the northern end of their spring migration, so of course the birds that we get would be breeding north of us,” says Holberton, who also is part of the ecological monitoring team working on UMaine’s DeepCwind offshore wind power initiative. “Those are the habitats that are really going to be the first and fastest to go in response to global climate change. If we don’t have some idea of what we’ve got now, we won’t have a feeling for how quickly population change is happening. And we certainly don’t want to exacerbate it by increasing mortality or making it more difficult for birds to reach their destinations.”
Although the collaborative nature of the Network is new, bird migration research in the Gulf of Maine has been going on for more than 100 years.
In the 19th century, Holberton says, the U.S. Department of Agriculture was interested in the impact of migratory birds on crops and newly seeded fields sometimes decimated by migrants. USDA created in 1885 the Office of Economic Ornithology and Mammalogy – a forerunner of the current U.S. Fish and Wildlife Service now housed in the Department of the Interior – which tasked lighthouse keepers in the Gulf of Maine with recording their observations about the timing of birds’ arrivals, the types and numbers of birds. In addition to the keepers’ scientific data, their observations became part of the cultural history of the life of a lighthouse keeper. Holberton has the original records, and says the birds became an important and welcome harbinger of spring for many of those in the isolated lighthouses.
“You can imagine being out there all winter and then you start seeing birds land, geese, bluebirds, robins, all this bright color,” she says. “The lighthouse keepers would write that it had been a tough winter, and they were glad to see the birds this year. So there is some interesting information in those notes.”
In England during World War II, as radar developed and its use became widespread, flocks of large migrating birds such as geese were detected and occasionally mistaken for squadrons of enemy planes.
It wasn’t until the 1960s, however, that scientists began basic research into the study of bird movements using surveillance radar in the Gulf of Maine, with studies documenting the directions in which birds were moving and the density of those flocks of birds. Scientists used ceilometers, a powerful light developed to determine the cloud ceiling at airports, to see and count birds as they flew through the beam of light pointed up at the sky.
Those techniques added critical knowledge about movements of flocks of birds on a large, landscape scale, but the researchers are now asking individuals more directly about their preferred direction. During so-called orientation release tests, first used in the Gulf of Maine by one of Holberton’s former graduate students, the researchers capture birds during the day and glue to the birds’ back a small, clear capsule filled with fluid that glows brightly in the dark. The birds are released after dark and their chosen direction is recorded by watching the movement of the capsule, often for up to two miles. The capsule falls off in 3-4 hours, after which time the bird is well on its way.
UMaine didn’t have a history of consistent research into songbird migration in the gulf until the start of the Network, which originated through an event that occurred about five years ago. At the root of the network was a 50-year-old seabird restoration project being done by the Holberton’s lab in collaboration with the U.S. Fish and Wildlife Service. It took a specific incident for things to turn. Holberton says she was on Petit Manan Island one early May day about four years ago with a graduate student studying the Arctic tern when the pair realized they were surrounded by songbirds.
They set up a mist net — a fine mesh netting used to catch birds — and within five minutes, they had captured a number of songbirds.
“U.S. Fish and Wildlife colleagues were there,” Holberton says, “and they could see that songbirds use these islands. They began to write their long-term, comprehensive management plan trying to understand how the islands they manage for seabirds during the breeding season are important for songbirds during other times of the year. They started to put songbirds on their radar screen.”
Working with USF&W and National Audubon, the network selected islands for research and banding based on the amount of involvement already present there in bird research, and also the level of logistical support the islands were receiving. The area of Metinic Island where Leppold’s banding station is located, for example, is owned by the Maine Coastal Islands National Wildlife Refuge, which services the banders with bi-weekly grocery deliveries and shuttling researchers on and off the island.