Feathering the nests

Long-planned work will restore tern breeding grounds

Marion harbormaster Michael Cormier on a sea wall that is to be replaced by a sloping wall on Bird Island. (Paul E. Kandarian for The Boston Globe)

MARION - The Bird Island tern restoration program seems finally to be on the horizon, even as the tiny circle of land, home to two types of protected sea birds, is slowly eroding.

Nearly $4 million in federal and state funding has been almost 10 years in coming, and the start of the work is still some years away. But with the state sending a letter of support to the Army Corps of Engineers requesting the restoration move ahead, the project is finally on track, said Carolyn Mostello, tern project leader at the Massachusetts Division of Fisheries and Wildlife.

"It was slow rolling for many years," Mostello said, adding that the project will take the next two years to plan. "When I started here in 2001, it was already in progress, and had been in discussion for a couple of years before that."

The 1.5-acre Bird Island is located at the entrance to Sippican Harbor. Storms and the ocean current pound away at its battered sea wall. As water washes over the island, low-lying ponds and marshes form, destroying the environment for terns, which need dry areas to nest.

Plans call for a replacement sea wall that will be sloped to better dissipate waves, Mostello said. And the low-lying wet areas will be filled in with a rocky layer topped with sand, likely dredged from the Cape Cod Canal, said Marion Harbormaster Michael Cormier. The canal sand is compatible with Bird Island sand.

The island is home to approximately 750 nesting pairs of roseate terns, birds on the endangered species list, and 1,900 nesting pairs of common terns, birds on the state's list of special concern, Mostello said.

Overall, Bird Island hosts about 22 percent of the entire roseate tern population in North America, and there are only three islands in Massachusetts - Bird Island, Ram Island in Mattapoisett, and Penikese Island, off Woods Hole - that hold roseate terns at all, birds that arrive in Massachusetts in April or May and migrate to South America in early fall.

The restoration work will be done when the birds are away, she said. Visiting the island when nesting terns inhabit it is an exercise in ducking and covering - the small birds are fiercely territorial and will dive-bomb and defecate on human intruders.

The project cost is estimated at $3.8 million, Mostello said. The Army Corps of Engineers is paying 65 percent, with the state picking up most of the balance. The New Bedford Harbor Trustees Council, which administers federal funding for cleaning up New Bedford Harbor, once ravaged by PCB pollution, also has allocated $541,000 for the project. The council has long paid for much of the management and monitoring of the three islands, Mostello said, and has been instrumental in helping to restore the tern population.

The Bird Island project recently was given a salt-marsh removal waiver, which helped move funding along. The recent letter from the state in support of the project was the last major bureaucratic hurdle.

There aren't many nesting areas for the fragile birds, which until the 1880s were abundant in the state, with hundreds of thousands of pairs of both roseate and common terns nesting on Muskeget Island off Nantucket alone. But the birds, about 15 inches long, were nearly hunted to extinction for their plumage, which was used for hats. The roseate tern's white body has a rosy tinge on the chest and belly during breeding season. The bird has a deeply forked tail and streamers extending beyond its wings when perched.

Pollution further decimated the terns. In 1975 the population stood at about 1,600 nesting pairs, most on Bird Island and Gull Island in New York. Restoration and management began on Bird Island in the 1960s, at Ram Island in 1990, and at Penikese Island in 1998, resulting in greatly increased tern populations on all three.

There are also plans in the works to fill in some wetlands on Ram Island, a project that has not yet gone out for bid, Mostello said. That island is roughly twice the size of Bird Island, while Penikese Island, which also hosts a significant seagull population, is about 75 acres.

By far, Bird Island needs the most work, Mostello said, as the tiny island gets smaller every year through natural erosion.

"There aren't many nesting areas, and they always nest off-shore" to avoid predators, Mostello said, adding that the numbers are "holding steady, but they can't grow, they're only losing ground. The whole island is eroding."

For more detailed information on the project, visit masswildlife.com, click on "Natural Heritage," and then the Buzzards Bay Tern Restoration Project.