MILBRIDGE, Maine — Maine Warden Scott Osgood has investigated many incidents of bald eagles found dead in the state.

But only one was electrocuted after fishing a lamprey out of Narraguagus Bay in Washington County.

Osgood’s accounting of that incident was briefly mentioned Wednesday morning in the Maine Department of Inland Fisheries and Wildlife’s July report.

Just after noon on April 25, Osgood found a banded, dead bald eagle beside a dead lamprey under power lines on a residential lawn in Milbridge. The lamprey was about 2½ feet long.

“I suspect that as the eagle flew over the lines with the eel in his talons, the dangling eel contacted the power lines and killed both predator and prey,” Osgood said Wednesday.

“It was kind of unique,” he said. “Eagles usually get killed by flying into wires in bad visibility or they break a wing and crash. I’ve handled quite a few, but never with an eel.”

As if that weren’t odd enough, Osgood took the eagle to Bangor where Inland Fisheries Bird Group biologists called in its leg bands and learned the raptor was more than three decades old when it died. That set a near record for Down East, Maine.

Osgood said the eagle was banded on Mount Desert Island as an eaglet 31 years ago.

That, in itself, was an eyebrow-raiser, because bald eagles don’t usually live that long in the wild, state wildlife biologist Brad Allen said Wednesday.

Allen said Charlie Todd, one of his former co-workers and Maine’s former state bald eagle expert, was involved in banding the Milbridge eagle. “He told me at the time, ‘That’s an old eagle,’” Allen said. “He’s not the oldest we have, but he was very close. Our oldest was 34 years old.”

According to the National Eagle Center website, an eagle that reaches adulthood might live 20 to 25 years. Seventy to 80 percent of eagles die before they reach adulthood at 5 years of age.

“This guy was pushing the age envelope and he probably lived all his life in eastern Maine,” Allen said. “There was no foul play, of course, but it’s unfortunate that an animal of that age and stature had to lose his life to a silly lamprey.”

In his career, Allen said, he’s seen a dozen eagles that died of electrocution, which is among the top five causes of bald eagle deaths, according to a Vanderbilt University study. But in those cases, the eagles were standing or nesting on power lines or flew into wires in poor weather conditions.

Allen said he had one case of a peregrine falcon that was electrocuted when it was carrying an eel that touched power lines, but the Milbridge eagle was a first.

He said eagle biologists encourage utility companies to space power lines greater than 6 feet apart to protect eagles from electrocution from flying into wires, because bald eagle wingspans are 6 to 7½ feet.

Allen said the strangest bald eagle electrocution death he investigated happened last May in Bangor when two sickly adult eagles came down from a nest. The female, who was found on a sidewalk, was under the influence of a toxin and was rescued and taken to Avian Haven, a rehabilitation practice in Freedom.

Her mate, however, was electrocuted. “The male was acting funny and he flew down and landed awkwardly on branches and fell onto power lines and was fried instantly in front of people watching,” Allen said.

This past winter, Allen said, he learned that the eagle had pentobarbital in its system. “Pentobarbital is a euthanasia drug used to put down animals, so he probably fed on a euthanized animal that was not buried properly.”

Both Allen and Osgood said eagles die all the time in Maine.

“Dead eagles are not uncommon,” Osgood said. “We get a lot of calls for them in the spring, because that’s when they’re more active. That’s when fish, like alewives, are running up the rivers. Alewives provide a lot of food for eagles at that time of year.”

He attributed the Milbridge eagle’s death to natural causes, albeit in a most unnatural manner.

“I’m surmising that that eagle had probably done that 100 times, carrying fish over the power lines that aren’t long enough to contact the wires, but he did it this time with an eel dangling more than 2 feet below him and got zapped,” Osgood said.