RICHMOND — One very full nest on Swan Island contains Maine’s first-ever documented occurrence of four eaglets in a single nest.

The eaglets born to a pair of bald eagles that have nested on the island since 2008 are believed to be only the fourth documented case of four eaglets in a single nest in the United States, according to wildlife biologists from the state Department of Inland Fisheries and Wildlife.

“It’s exciting to see,” said Kendall Marden, a state wildlife biologist whose territory includes Swan Island, a state wildlife management area in the Kennebec River between Richmond and Dresden. “It’s a remarkable event.”

Marden said the eaglets are likely over three months old, and are just starting to fly.

“They’re just taking their maiden voyages now, cruising about,” he said.

Biologists had seen the pair of eagles preparing the nest for some time, but didn’t realize, until recently when the staffer stationed on Swan Island spotted them, there were four young ones in the nest.

Marden said the four eaglets were likely more challenging for their nesting parents — like four children would be to any parent, compared to one child.

Marden said the adult eagles at Swan Island have done their part ensuring the survival of all four eaglets, but it’s nearing the time the young will have to be more independent. He said that includes learning to fly and feed on their own, during one of the critical time periods in an eagle’s life. If eaglets can survive until they learn to fly, their chances of surviving their first year reaches 75 percent.

Marden said the adult eagles appeared to have been successful in producing at least one eaglet in their first year on the island in 2008, but were unsuccessful the last two years.

Marden said the four eaglets are a milestone for eagle recovery in Maine.

As recently as 40 years ago, bald eagles were battling extinction. Widespread use of the pesticide DDT was responsible for wiping out certain wildlife, especially birds of prey. Nesting pairs in Maine numbered around 20 and things looked bleak.

Wildlife agencies worked hard to recover and protect the species.

Marden said Swan Island is a good example of one of the main objectives used in eagle recovery — the protection of nests. There are three protected eagle nesting sites on the island, and three nesting pairs of eagles.

In 2007, the bald eagle was removed from Maine’s list of threatened and endangered species, with more than 500 nesting pairs in the state today.

Keith Edwards — 621-5647

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