Birds
The Maine Event
Even after 34 years of successful seabird restoration, determined predators are still making it tough for scientists to declare a conservation victory.
By Pete Salmansohn
From the deck of our tour boat, the island known as Eastern Egg Rock looks like a rocky weed patch crowned with a halo of swirling terns, whizzing puffins, and fast-flying eider ducks. When a show-off puffin flies close to the boat, whoops of joy and applause erupt from the 70 or so passengers lining the upper and lower decks. Roughly 5,000 ecotourists make the trip out to this now famous Maine island each summer to see the clownlike puffins that have returned after a nearly 100-year absence.
Eastern Egg Rock is where Steve Kress, a friend, colleague, and director of National Audubon’s Seabird Restoration Program, began his efforts in 1973 to restore Atlantic puffins to historic nesting islands in the Gulf of Maine. It is also one of the islands most commonly visited by birdwatchers, since it’s only about five miles from the mainland. After 15 years of working as an Audubon education coordinator and narrator on boat tours, I’m still excited to share this conservation success story, and to witness the cheers of inspired visitors.
Over the years I’ve been asked a lot of questions: Do puffins mate for life? Where do the birds go in winter? How deep do puffins dive? But of all the inquiries, the one that is perhaps the most challenging for me to answer is: How long do you think Audubon will have to continue this work? In other words, when can we declare victory and move on? It’s a question that those of us who have worked on the boats have been grappling with since the ecotourism program began in 1987. And the answer is still difficult to explain. We work with rare and endangered species in an area of the country where the balance of nature has been seriously altered. Thus we’ve come to the sobering conclusion that we’ll never be able to pack up our tents and leave the seabirds to their own devices. The predators simply won’t let us.
Mink, great horned owls, gulls, black-crowned night-herons, raccoons, and even peregrine falcons have discovered that they can make a decent living picking off tern chicks and eggs, and occasionally adult puffins and terns. Perhaps there was a better balance between predators and prey centuries ago, before European settlers so radically changed the ecology of the coast of Maine. These days predators often have devastating impacts on seabird colonies. One of the most startling examples occurred in 1988 when a mink swam several miles from the mainland or an adjacent wooded island to Eastern Egg Rock and killed 26 common terns and five federally endangered roseate terns. We were astounded.
During more recent summers on Pond Island National Wildlife Refuge, in the mouth of the Kennebec River, Audubon biologists wearing night-vision goggles watched in dismay as great horned owls that had flown over from the mainland chased and captured swift-flying terns and Leach’s storm-petrels in midair. No one on the project had ever heard of great horned owls hunting on the wing before. The owls also killed terns sitting on the ground, and their mere presence on the island caused widespread panic and wholesale abandonment of nests in the tern colony.
In 2004, and periodically during other years, peregrine falcons—only recently recovered after being nearly wiped out by DDT—pursued and killed terns, puffins, and razorbill auks on several Audubon-managed islands. These attacks and others posed a huge conundrum: What do you do when one endangered species is picking off similarly rare and threatened birds, especially when you’re responsible for the survival of the species being preyed upon?
This paradox also applies to gulls. Before the Migratory Bird Treaty Act of 1918, plume hunters collecting feathers used to adorn ladies’ hats and dresses slaughtered gulls by the hundreds of thousands, if not millions. The newly organized National Association of Audubon Societies worked against extremely difficult odds in the early 1900s to keep the last gulls in Maine from being killed. Nowadays, with tons of free food in the form of garbage, fishing waste, and discarded lobster trap bait, gulls are thriving, outnumbering other coastal bird species in Maine and causing serious problems for restored terns and puffins.
In addition to eating their eggs and chicks, gulls have displaced terns, forcing them to use less suitable breeding places—often near the mainland, where mink and owls abound. Nearly 16,000 pairs of great black-backs and more than 28,000 pairs of herring gulls now nest on roughly 230 islands. In comparison, only 11,000 pairs of terns nest on just a handful of islands and 800 pairs of puffins inhabit only four breeding sites, all of them managed for species diversity by Audubon and the U.S. Fish and Wildlife Service.
“What we’re trying to do as seabird stewards,” says Kress, “ is to replicate sustainable seabird communities in a world that’s been radically changed by the activities of humans. Most of the islands that terns historically nested on are basically unusable because gulls now dominate those sites. And the changing patterns of land use along the New England coast, where thick forests have taken over old farm fields, has provided owls and mink with ideal places to live.”
The survival of Maine’s puffin and tern colonies now rests largely on the shoulders of a new crop of young biologists who are willing to endure near-freezing night temperatures, hordes of midsummer mosquitoes, infrequent hot showers, and pounding rainstorms with 50-mile-an-hour winds that occasionally blow down their tents. These biologists—mostly college and graduate students eager for experience in their field—stand watch over the colonies from May to mid-August, using a variety of methods, such as breaking up gull nests and setting out live traps, to keep hungry and dangerous predators in line.
“Over the 34-year history of the program, we have tried many approaches to reducing the impacts of predators,” says Kress. “We favor humane ones whenever possible. The best case is our present management strategy for gulls. We found that by setting up camp on islands early in the egg cycle for herring and great black-backed gulls that the gulls will not nest on the islands. When they do, we remove the eggs. Occasionally, a non-nesting gull will specialize in killing tern chicks, and in newly restored small puffin and tern colonies we occasionally shoot such birds as a last resort.”
“Without some form of predator control,” adds Audubon Island research coordinator Scott Hall, “terns wouldn’t produce enough offspring to sustain state populations, and puffin restoration in Maine would essentially be for naught.”
Audubon’s Seabird Restoration Program now operates seven island field stations along the Maine coast, and each year we watch as a living, flying chessboard takes form. It’s not unusual to see a group of terns get attacked at one nesting site, then resettle at another. “When our Jenny Island [Casco Bay] tern colony was hit by three successive minks in 2001,” says Hall, “the birds dispersed to several other island sanctuaries, and more than a thousand of them flew south to Stratton Island [about 28 miles away, in Saco Bay] and nested there.” In June of 2002, however, one very determined black-crowned night-heron attacked the terns on Stratton Island and completely decimated about 500 nests, eating both eggs and chicks. The common and roseate terns panicked, and many of them left. But soon thereafter observers on New Hampshire’s Seavey Island sanctuary, 27 miles to the south, saw an increase in the number of nesting roseate terns.
Despite occasional losses, all of the three species of pelagic terns—common, Arctic, and roseate—are doing better. Tern numbers have grown on these islands from 3,815 pairs in 1977 to 10,827 pairs in 2006.
When people board the tour boats, they come not only to see puffins and seabirds but also to learn about how these charismatic animals spend their lives. If I’m answering the question “Where do puffins go in the winter?” for the hundredth or the five hundredth time, it’s okay, because the passengers are full of wonderment and appreciation. It takes a lot more to explain the notion that we have to commit to continuing this work without an end date in sight because ecosystems are very complicated, and this one has been changed in many subtle—and not so subtle—ways, above and below the water’s surface. “When this work started, it was with the notion that we would one day finish and be able to back away,” says Kress, 34 years after beginning his research on Eastern Egg Rock. “But I no longer envision getting to that place. The whole ecosystem has changed as a result of human presence. We have to redefine the balance of nature—and we’re part of it.”
Pete Salmansohn has worked at Maine’s Hog Island Audubon Camp since 1980, and joined Project Puffin in 1992.
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