BY SHANNON BRYAN

A lot of visitors assume that Acadia is only the 40,000 acres of Mount Desert Island,” said John Anderson, professor of ecology and natural history at College of the Atlantic in Bar Harbor. “It isn’t.”

“The park has over 120 islands that it owns or has easements on,” he said. “That’s pretty substantial.”

Among those are 13 important seabird islands—rocky offshore spots relatively free from predators where cormorants, gulls, black guillemots, and Leach’s storm-petrels go to nest and raise young. The crown jewel of those, Anderson said, is Schoodic Island.

Located about a half mile off the coast of the Schoodic Peninsula, 67-acre Schoodic Island has large nesting colonies of gulls and cormorants.

“It’s very close to the shore, and yet it’s managed to hang onto its birds,” said Anderson. “It’s absolutely fascinating.” As College of the Atlantic faculty and the field station director at the college’s Alice Eno Biological Station on Great Duck Island, Anderson has studied the region’s seabirds for three decades.

Great Duck has possibly the oldest gull colony in the northeast, he noted. Since 1999, he’s taken teams of students out to Great Duck to study the gulls there, with some students staying on the island for weeks at a time.

Two summers ago, with support from a grant from Friends of Acadia, Anderson and his team were able to expand that research to islands within Acadia National Park.

“Acadia National Park is so critical because we’re right on the ecotone—a dividing zone between two very different floras and faunas,” Anderson said. “We’re right where a lot of northern species end up and where a lot of southern species end up.”

This means changes to the health and populations of the region’s gulls could have far-reaching impacts – particularly as colonies face threats from climate change and avian influenza.

College of the Atlantic student and seabird researcher Autumn Pauly holds a herring gull (Larus argentatus) chick on Great Duck Island. (Photo by Sam Mallon/Friends of Acadia)

The Seabird Study Grant from Friends of Acadia enabled Anderson and his students to conduct a survey of the park’s seabird islands, which hadn’t been done in a decade. The survey identified which of Acadia National Park’s islands had seabirds.

“There’s a limited number of islands that are suitable for seabirds,” Anderson said. “If the island has a dense spruce forest, it’s not going to have nesting seabirds.”

The survey also tallied the number of nests on several of those islands and mapped where each of those nests was located.

“We have high precision GPS, so we’re able to get the nests mapped to within half a meter of accuracy,” said Anderson. The data will enable researchers to track population shifts over time and as the climate changes.

“Somebody can go back five, 10, 20 years from now, and they can see not only whether there were birds there, but whether they’re
nesting in the same location.”

A herring gull (Larus argentatus) chick. (Photo by Sam Mallon/Friends of Acadia)

The grant also enabled Anderson and his students to deploy solar-powered GPS tags on herring gulls on Schoodic and Shabby Islands. The tags tie into the cellular network, recording the gulls’ movements.

“That allows us to see movement patterns: Where are they coming from? Where are they going?” said Anderson. Gulls from Great Duck have worn different GPS tags for the last several years, and being able to now compare the comings and goings of both populations helps researchers better understand the ways in which the colonies might differ or overlap.

The GPS tags are in addition to long-used colored bands researchers place on gulls’ legs. Together, they provide data as part of a longer-term study helping researchers understand where these birds go and how different colonies interact.

“Gull are incredible creatures of habit,” said Anderson. The gulls from Great Duck tend to travel to Little Cranberry Island and locations west, like Deer Isle and Blue Hill Bay—but never to Frenchman Bay. Gulls from Schoodic Island go to Winter Harbor, Bar Harbor, and Frenchman Bay—but never to Blue Hill Bay.

The initial data is already revealing significant differences in movement patterns between birds from different islands, Anderson said. This winter, the team is watching post-breeding data as the birds disperse to wintering areas.

“If they’re like Great Duck birds at all, some of them are probably going to stick around…and some of them may be off to Virginia,” he
said. “We could get birds that go to Bermuda, go to Chesapeake, go to Florida, or Louisiana, or the Great Lakes.”

Gulls sometimes detour to unexpected places, too.

“We had one very odd bird that…took off from Great Duck, flew down the coast, and, for reasons I still don’t understand, when he got into New Hampshire, he hung a right and spent a day or two hanging out in the White Mountains,” Anderson said. “Then he came back down to the coast and went on down to Virginia.”

Herring gull eggs. (Photo courtesy Julia Walker Thomas)

The surveys and tracking are important for protecting the park’s natural resources and biodiversity, said Anderson. But there’s an even more immediate reason: “For the last number of years, we’ve been aware of a form of avian influenza—highly pathogenic avian influenza (HPAI)—which has had devastating effects on seabird colonies in Europe, Alaska, and more recently down the Pacific coast.”

It’s also found its way to Maine.

HPAI is a changing virus, he said, meaning the actual structure of the virus can shift very suddenly, and that fools your immune system. It can also jump species.

“It started showing up in Maine seabirds. It’s now showing up in mink. It’s showing up in fox. It’s showing up in seals,” said Anderson. “And there are a few cases of people getting it. So that’s really worrying.”

With seabird populations that frequent the mainland, and a national park that sees millions of visitors every year, monitoring is essential.

“From Acadia’s point of view, part of it is about resource management protection. Part of it is also about visitor experience. We want people to be safe,” said Anderson. “If HPAI were discovered in birds, we’d want to know which islands are involved. We also want to know where those birds are going and how they might interface with the general public.”

Last summer’s monitoring included bird counts on several offshore islands, including Great Duck Island and Mount Desert Rock. Nearly 100 swabs were taken from adult birds and some chicks, providing a good measure of possible infection levels. Results are not yet in, but Anderson noted that no significant seabird mortality was detected in any of the visited islands.

Tracking data from those GPS tags is critical to the epidemiology, Anderson said, “because gulls don’t migrate. They disperse.”

Much like college students leaving a central campus to go home for the summer, some stay close to campus, others scoot off to far-flung
states.

“Knowing where the birds are going gives us potential insights into where they might pick up disease and also spread disease,” Anderson said. There remains a good number of unknowns with HPAI. Researchers don’t yet have answers to critical questions.

“We’re learning as we go,” he added. “To me, the first step of learning is knowing what you’re working with, and thanks to Friends of Acadia, we’ve got such a huge jump on it.”

Charlotte Willis of New Rochelle, NY and her “new friend,” a herring gull, hang out in the Schooner Head Overlook parking lot in Acadia National Park. (Photo by Avery Howe/Friends of Acadia)

Monitoring the seabird islands is additionally important as the climate changes.

“We’re going to be seeing not only sea level rise, but we’re also going tobe losing vegetation as a consequence of changes in temperature,” said Anderson. “Schoodic Island isn’t going to be Schoodic Island anymore. It’s going to be two little islands because of sea level rise. The vegetation on it is probably going to be very different vegetation.”

One of Anderson’s students spent a recent summer identifying vegetation around herring gull nests to better understand what vegetation, or lack thereof, encourages or discourages nesting.

“I think it’s critically important to monitor,” said Anderson. “I think it’s critically important to try to understand. These are all things the Friends of Acadia grant encourages us to do.”

And while the research is crucial, the work has another meaningful effect.

“The Friends of Acadia grant is so great because it gave me a perfect excuse to take half a dozen really bright kids and put them on an island doing real research and handling real birds—for a purpose. But also, in the process of handling those real birds, falling in love with them too.”

The Alice Eno Research Station and lighthouse on Great Duck Island, where College of the Atlantic students conduct seabird research. (Photo by Sam Mallon/Friends of Acadia)