Posted on Sat, Jul. 29, 2006

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Eagles hatched in Contra Costa

By Denis Cuff

CONTRA COSTA TIMES

Nick Dunlop

One of a pair of bald eagles that hatched in Contra Costa County.

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A pair of bald eagles has nested and hatched offspring in Contra Costa County for the first time documented, marking another milestone in the recovery of the national bird.

An East Bay Municipal Utility District ranger earlier this month discovered the nest with two eaglets on remote lands used as a pollution buffer for the San Pablo and Briones drinking water reservoirs north of Orinda.

The two eaglets, a sister and brother, learned to fly and left the nest.

Their appearance mirrors a national trend in which the acrobatic flier with the fierce look is expanding its breeding territory after teetering on the brink of extinction in the 1960s and '70s.

"To have open spaces in the East Bay where you have these beautiful birds is really wonderful," said Roger Hartwell, EBMUD's supervising fishery and wildlife biologist. "You may never see a bald eagle. They avoid people, but it's rewarding to know they're out there."

Wildlife experts say they can find no documented evidence of a Contra Costa bald eagle nest in records dating back to the 1920s.

They might have lived in the area earlier, maybe even centuries ago.

Biologists offer several reasons why the proud eagle parents picked the Contra Costa site to build a home:

• Pine trees planted on water district reservoir lands between Orinda and El Sobrante have matured, providing attractive perching and nesting spots.

• Bald eagle numbers are up nationally since the 1970s, when the eagle benefited from habitat protections and a ban on the pesticide DDT, which weakened eagle egg shells.

Bald eagle nesting pairs in California increased from about 30 in 1977, when they all lived north of Lake Shasta, to about 200 currently, according to the state Department of Fish and Game.

• Conservationists planted 70 eaglets from Alaska and other areas in Big Sur between 1986 and 2000. Organizers hoped the picky birds would settle along the central coast between San Francisco and Santa Barbara.

It turned out the young eagles weren't big beach fans, but settled inland around reservoirs flush with fish, an eagle favorite.

"We believe the eagle pair in Contra Costa are likely related to the eagles introduced to Big Sur," said Kelly Sorenson, executive director of the Ventana Wildlife Society, a partner in the project.

Because eagles tend to build nests where they grow up, planting eaglets speeded their spread through California, Sorenson said.

EBMUD officials say they don't know where their eagles came from.

The pair acted with such stealth that they apparently built the nest two years ago and escaped attention until weeks ago.

The water district is not divulging the nest location to minimize the risk of human disturbance.

It is not unusual for bald eagles to visit the Bay Area. But there were no known nests in the Bay Area in 1996, when a pair built a nest overlooking Del Valle Reservoir near Livermore.

The mom was an Alaskan bird introduced to Big Sur as an eaglet.

The Del Valle pair became instant media stars. Many visitors came to watch the family through binoculars and spotting scopes from the other side of the lake.

Some bird watchers worried the attention would drive them away.

The pair stayed, however, until three years ago, when the couple moved onto private land and continued breeding there, park officials said.

"We don't think human activity drove them away," said Joe Didonato, the East Bay Regional Park District stewardship manager.

Meanwhile, another bald eagle nest was discovered this year in a rugged site off limits to the public on lands draining into the Calaveras Reservoir in Santa Clara County.

That means there are at least three active Bay Area nesting sites on large swaths of wild territory.

Hartwell of EBMUD said the new eagle nest is a tangible result of his agency protecting its reservoir lands and managing them to protect wildlife and water quality.

Meanwhile, the federal government is considering removing the bald eagle from threatened status because of its rising numbers.

Whether or not that happens, one Contra Costa conservationist says he is delighted by the eagle nest on his home turf.

"They are just awesome, extremely powerful birds," said Mike Williams, vice president of the Mount Diablo Chapter of the Audubon Society. "I'm glad they're coming back."

Contact reporter Denis Cuff at 925-943-8267 or dcuff@cctimes.com.