BAR HARBOR — Recent aquaculture projects such as the proposed Goose Cove and Thomas Bay oyster farms have drummed up more than a few controversies.
One concern of some oyster farm opponents is that the facilities would attract more seabirds to the areas near the Hancock County-Bar Harbor Airport in Trenton, potentially causing a higher probability of bird-airplane accidents.
But one College of the Atlantic (COA) researcher is studying to find out whether or not that likelihood is real.
Professor John Anderson is heading up research that tracks herring gulls to see where they fly, but also, for the first time, how high they go.
COA in partnership with the Island Institute this summer outfitted eight herring gulls with lightweight “backpacks,” each with a solar-powered global positioning system (GPS) receiver and small radio that tracks the birds’ locations and altitudes every 10 minutes. Once a gull is within range of Great Duck Island or Mount Desert Rock, the data compiled is downloaded to base stations there.
Anderson, a former teacher of one of the proposed Thomas Bay oyster farmers, said initial research has shown that there have not been flocks of gulls to the Goose Cove farm since the cages were dropped in two weeks ago. He also said early data suggests that gulls don’t fly high enough to hinder the path of an airplane.
So far, Anderson said, the birds’ average flying altitude is 50 feet. The highest a bird has flown is 124 feet. Planes are not supposed to fly less 500 feet above open spaces such as woods or water, or less than 1,000 feet above built up areas, except upon take-off and landing.
“Gulls are not a problem for airplanes,” he said. “If I was worried about bird strike, I’d be lobbying for people to get rid of their lawns.”
Canada geese, he said, are more likely to cause safety issues with airplanes.
Geese graze in groups on the lawns surrounding the airport and are “exploding” in population, according to Anderson. But he doesn’t discount the possibility that an oyster farm could attract more gulls in the future.
“There could be a big spike,” Anderson said. “We just have to keep watching this experiment.”
The eight herring gulls outfitted with the GPS transmitters also are part of a larger research project that tracks both herring and great black-backed gulls on their migration paths using colored bands.
Over the past decade, the gull population in New England has dropped some 40 percent. Should those species become extinct, it could be detrimental to the coastal Maine ecosystem, Anderson said.
“If we lose the gulls, it could be a big deal,” he said. The gulls protect eider duck eggs and are effective at chasing off predatory crows and ravens.
Over the past four years, Anderson and other researchers have enlisted the help of citizens around the country to look for gulls with colored aluminum bands on their feet to see where they go in the winter and if they return.
The birds are banded with aluminum tags that are registered with the U.S. Fish and Wildlife Service around one leg. On another leg is a colored band that signifies the island of origin.
The purpose of the project is to discover why the New England population is in decline. This summer, Anderson and his team attached bands to 100 herring and great black-backed gulls.
“We’ve had banded bird sightings in New York, Florida, Mississippi and Louisiana so far,” he said, as well as sightings from the Carolinas and the Great Lakes region.
Anderson said one Somesville resident has seen the same gull in her yard repeatedly. One bird spotted in New Jersey earlier in the year came back to Mount Desert Island this summer.
“To me, this is citizen science at its best. It involves the public getting answers to a really real question about gulls,” Anderson said. “It gives us some really valuable information.”