In a few months gulls will patrol the dunes of South Beach seeking the ill-grasped sandwiches of naive tourists, but on Thursday the deserted area was the domain of “the bird.” That’s what contractor Michael Warminsky calls the extremely low-flying, modified Bell 206 helicopter that began sniffing Vineyard beaches this week for what remains of the physical legacy of the Vineyard’s encounter with World War II.

With its undercarriage-mounted array of magnetometer-studded limbs, “the bird” flies perilously close to the ground searching for buried bombs.

“It’s just like cutting the grass,” said Mr. Warminsky, project manager for the contractor UXB, as the swaying helicopter combed the dune grass on Thursday, eliciting gasps from members of the Edgartown conservation commission, who were lucky enough to catch the show while on an unrelated site visit.

“I think he’s showing off now, he’s got an audience,” said Marilyn Wortman of the Edgartown park and recreation committee as the pilot nimbly swerved around a salt-spray-stunted pitch pine.

“There may be some truth to that,” said Mr. Warminsky. “We always tell them to fly as low as they comfortably and safely can.”

Since December the Army Corps of Engineers has been engaged in a $5.6 million effort to close the books on one of the more peculiar chapters in Martha’s Vineyard history, methodically surveying Tisbury Great Pond, South Beach and Chappaquiddick by land, sea and air for potentially dangerous ordnance. Seventy years ago, while the world was at war, the Vineyard was a Naval proving ground and the three sites all served as aerial dive-bombing target ranges for the screaming Grumman F6F Hellcats that emptied their practice (and not-so-practice) rockets all along the Vineyard coastline.

On Thursday the unusual helicopter (operated by subcontractor Battelle) dangled above what was once the Katama gunnery as part of a series of transects the Army Corps will survey in the next week, before beginning to dig for and dispose of the rusted explosives.

Once boasting a moving machine gun target range on an oval rail system that spanned hundreds of yards of South Beach, the Katama gunnery at the war’s peak was ablaze with the whizzing bullets of truck-mounted machine guns and 20 mm cannons. It opened in August of 1944, at a cost of $297,984.30, and with a bang, as documented by the Gazette:

“The terrific bombardment which shook Edgartown yesterday afternoon about 2 o’clock, was not a celebration of the completion of the range, but is said to be due to experimental work off of the South Beach,” an article reads. “It is nothing new to Edgartonians, although the ferocity of the attack was unparalleled.”

Throughout the war the Navy had a sometimes strained relationship with the Vineyard, one that included a long-standing public dispute with the elderly Edward T. Vincent, whose Katama farmland the Navy once threatened to seize by eminent domain for use as a practice field for Annapolis’s football squad. The Gazette’s wartime archives are filled with yellowed communiques from fumbling and overworked Naval public relations employees.

After decades of erosion the oval tracks of the machine gun range are now some 160 feet out to sea but the Army Corps is determined to find whatever remains of the rockets that may be buried only a few feet under the sand.

Although removed from the war by decades, the ordnance remediation work is not without its lethal hazards. Just two weeks ago a diver working with a private surveying team contracted by the Army Corps was pulled unconscious from the icy waters near Cape Pogue on Chappaquiddick as a result of an overinflated dry suit. The diver was resuscitated by team members and has recovered, but Army Corps project manager Carol Ann Charette said the corps spares no expense providing for the surveyors’ safety. The aerial surveying work has been delayed for weeks after predictably unpredictable Vineyard winter weather alternately rendered Tisbury Great Pond ice-free and frozen-over within a matter of weeks. Ordinarily work over water requires a boat rescue team, but the corps has had to act quickly to keep up with the changing conditions.

“If you’re doing it and there’s ice on the pond then you have to have an ice rescue team available in the unlikely event that the helicopter has to be abandoned,” Ms. Charette said.

Luckily on Thursday all such precautions proved superfluous and, stepping onto the Martha’s Vineyard Airport tarmac at dusk in full-body flotation suits after four hours of death-defying survey work, Batelle pilot Doug Christie and navigator Marcus Watson looked relieved to be back on terra firma.

“You’ve heard of the expression 98 per cent boredom and two per cent sheer terror? Well, this is the exact opposite of that,” said Mr. Christie. He and Mr. Watson have been working as a team flying the magnetometer equipment for contractor Battelle for four years in work that has brought them to the far corners of the globe. The magnetometer array might look unwieldy from the ground but Mr. Watson said that it added a measure of stability, much like a balancing beam.

Although it is designed to find metallic objects, on Thursday, after a project supervisor saw a local ad for the lost Chilmark black Labrador retriever Olive (and its attendant $5,000 reward) Mr. Christie joked that the ordnance search was doubling as a high-tech dog hunt.

“[The supervisor] said, ‘Whatever you do just call me and tell me what the GPS coordinates are for the dog,’” he said.

Earlier in the day Ms. Charette slapped down on the flatbed of her pickup truck a map of the remaining areas on the Island that the Batelle team would survey in the coming week. As she did so the helicopter banked sharply and headed towards Wasque, an area where three years ago the Navy discovered two 100-pound, and very live, bombs.

Long-time Chappaquiddick resident and Edgartown conservation commission member Edo Potter surveyed the map and reflected on a peculiar collection of hers.

“I have a whole bunch of bombs at my house,” she offered. “I know that I should give them up but I’ve had them for years.”

“You should at least have somebody check them out to make sure that they’re not dangerous,” replied Ms. Charette, mildly horrified.

“The little ones are empty . . . and the big one is too,” Ms. Potter said after some hesitation.

For Ms. Potter the buried bombs are more than just military debris, they are relics from her childhood.

“I remember the landing crafts that came and unloaded on East Beach when they were practicing for the Normandy beaches,” she said. “I was little, eight years old, and my sister was ten and we’d go down there and the Navy was so happy to see us they’d give us C-rations. And I thought that was the greatest thing in the world.”