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Bald eagles make a comeback

Bald eagles, once almost completely vanished from California's Santa Catalina Island, are staging a comeback, beginning to hatch eggs in the wild without human intervention.
/ Source: NBC News

Standing on a remote hillside, keeping an eye on a nest with a newly hatched bald eagle chick, wildlife biologist Peter Sharpe was obviously elated.  “This is very cool,” he said, “I’ve been waiting for 10 years for this to happen.”

Sharpe was talking about the fact that bald eagles, once almost completely vanished from here, are staging a comeback, beginning to hatch eggs in the wild without human intervention.

For the past 27 years, the Institute for Wildlife Studies, the organization that employs Sharpe, has conducted a program to bring back the bald eagles that once populated the island.

And what caused their disappearance in the first place? The problem is that the eagles have high levels of the now-banned insecticide DDT in their systems.  The chemical causes many birds to lay eggs with abnormally thin shells that don’t last long enough to hatch properly. A large quantity of DDT, a substance that breaks down very slowly, remains in the Pacific Ocean off the California coast.

“This is 35 years since DDT was last used in the U.S.,” said Sharpe, “And we’re just now beginning to get successful hatchings. So we need to look at the consequences.”

From 1980 to 1986, 33 bald eagles were released onto Catalina Island in an effort to repopulate the birds there.  Some of the eagles matured and formed breeding pairs, but in 1987, the first eggs laid by the reintroduced birds broke. In 1989, scientists began trying to lend a hand to nature.

Midwive to the birds
For a decade now, Sharpe has been acting as midwife to the birds, snatching the eggs from their nests, swapping them for fake eggs to fool the parents, then nurturing the real eggs in incubators until the chicks hatch.  The chicks are then returned to the nests while the parents are out gathering food. If too few chicks hatch, captive-born ones from the San Francisco Zoo are fostered into the nests. Since 1980, more than 100 bald eagles have been released on Catalina Island.

Sharpe and other scientists are not yet sure why some of the bald eagles have begun laying normal eggs.  Perhaps something is causing them to alter their diet, resulting in lower DDT levels. One theory is that some eagles are eating more fish and fewer marine mammals that tend to retain more DDT. Whatever the cause, it’s a welcome development.

“I think it’s the first sign we’ve had in the whole recovery program that they might be able to make it on their own,” said Ann Muscat, the President of the Catalina Island Conservancy, working with the Institute for Wildlife Studies on restoring the eagles. 

Those eagle eggs have been a bit of a political football in California conservation circles.  A huge lawsuit, settled in 1981, forced the Montrose Chemical Corporation and others to pay $140.2 million in damages for dumping DDT into the ocean. The settlement allocated $250,000 a year for eagle restoration in Catalina. But in 2005, the trustees of the settlement voted to allocate most of the funds to eagle restoration programs elsewhere on California’s Channel Islands because they felt the odds of eggs hatching successfully in the wild on Catalina were pretty remote.

Now that the eagles have proven that theory wrong, the Catalina Island Conservancy is hoping that the trustees will reconsider. 

Soaring future?
“This is one of the few places where people can see bald eagles in their natural habitat,” said Muscat, noting that Catalina Island gets 1.2 million visitors a year. “Hopefully,” she added, “we’re going to create a place that these eagles can live for a very long time and people can see them and enjoy them.”

The only eagles most of those visitors see are a group of life-size bird statues on the waterfront in Avalon harbor, or “Pimu,” a female bald eagle that has to live in captivity because she’s disabled with a broken wing.  Naturalists dream of a future where eagles are a frequent sight, living here in the wild and soaring magnificently in the skies overhead.