Group of California condors recently spotted flying over the East Bay
California condors are moving farther into the East Bay.
Seven of the endangered birds flew north into Alameda and Contra Costa counties on a circuitous aerial tour on Aug. 18, the conservation group Save Mount Diablo said Monday.
The three-hour flight began shortly after noon, when they left their previous evening's roost site south of Ohlone Regional Wilderness.
They soared over Pleasanton and Sunol, near the intersection of interstate Highways 580 and 680, over Dublin and Tassajara, and ventured north over Mount Diablo's Pine Canyon near Castle Rock -- which Save Mount Diablo said is a possible future nesting site and where the group helped reestablish endangered peregrine falcons.
The condors flew as far north as Lime Ridge Open Space, west of Clayton, before veering east -- the furthest north the birds have flown in Contra Costa.
Save Mount Diablo said the condors circled Mount Diablo before heading south over the outskirts of Livermore and then spending the night in the mountains near Lake Del Valle.
The condors, fitted with radio and GPS transmitters, did not appear to have landed during their time in the area.
Save Mount Diablo said they got the information from wildlife biologist Joseph Belli, who volunteers for the California condor recovery program at Pinnacles National Park. He also works closely with Save Mount Diablo and pays special attention to birds ranging up and down the Diablo Range.
"I've been monitoring condors for nearly 20 years and it's wonderful to see groups of them exploring further north in the Diablo Range every summer for the past four years," Alacia Welch, the condor program manager at Pinnacles National Park, said in a statement. "We would rarely know of these long-range flights if it weren't for the GPS transmitters on some of the condors. I wouldn't be surprised if these summer forays continue into the future, so all you eagle-eyed condor enthusiasts should keep an eye to the sky."
Six condors took an exploratory flight near Mount Diablo about the same time last year. It was the first flock in Contra Costa County in 100 years. Two of them were also among this year's group.
The most recent visitors were a blend of condors raised in captivity and products of wild nests in southern San Benito County and Pinnacles National Park. Pinnacles and the Ventana Wildlife Society co-manage the flock, managing release sites and monitoring the birds from the park and Big Sur.
The central California flock consists of roughly 100 free-flying condors, ranging from north of Paso Robles and San Luis Obispo to southern Santa Clara County and occasionally beyond.
Save Mount Diablo said that number will increase toward the end of the year, when 10 to 12 young condors raised in captivity will be released.
