California condors exploring Diablo Range
A dozen condors were recorded flying over the Diablo Range last month, suggesting the rare species is exploring new territory in the Bay Area's rolling grasslands, plateaus and peaks.
“It's the most condors we've seen in that area at one time, ever,” said Kelly Sorenson, executive director of the Ventana Wildlife Society, which reintroduces captive-bred condors to their historic Central Coast habitat. “The population is growing in size, and it's also expanding its range.”
On Aug. 24, two of the birds were spotted soaring over Mount Hamilton, only 20 miles east of downtown San Jose, sending astronomers and other Lick Observatory staffers rushing outside, eyes to the sky, after a radio announcement.
“It was so exciting. They're just such huge majestic birds,” said observatory astronomer Elinor Gates, who raced out of her residence with binoculars and cameras.
The pair — one released in the mountains near the coast of San Simeon and the other in Pinnacles National Park — flew from the west to the east, over a building that houses the Observatory's historic 35-inch refractor telescope.
The San Simeon bird was named Xakkin by the local Rumsen Tribe. Its name, which means “to eat ravenously,” was selected because of his enormous appetite and willingness to bully through a congregation of other feeding condors. The Pinnacles bird has not been named.
Since their release, they've joined a large flock that flies between Pinnacles and Big Sur — and, increasingly, the Diablo Range north of Highway 152, which runs from Watsonville to Merced. Historically, its core range is south of Highway 152.
“They're going out there because it's great habitat,” said Sorenson. “It's absolutely beautiful ranch land that supports a whole
array of species.”
The huge, wild birds — with 10-foot wingspans — once thrived but vanished because of lead poisoning, hunting and habitat destruction.
The California population has climbed from 20 in 2002 to 93 today. But lead poisoning continues to kill the birds. Scavengers, they rely on carrion — the carcasses of deer, squirrels and other mammals — for food. If those animals were killed with lead bullets, the condors ingest it and perish. Although a ban on the use of lead ammunition went into law in 2019, hunters are not reliably able to find non-lead ammunition, especially for .22-caliber bullets.
Summer is the ideal time for condors to explore, because the columns of rising air, called thermals, are created by the warming of the ground by hot sunlight. Thermal lift eases their flight.
Their wanderings “foreshadow future condor activity,” Sorenson said. “They check it and make a little mental note of where it is. Then they come back again.”
“Then, over time, more and more birds show up in a particular area. It becomes part of the range,” he said.
Five condors were sighted above Mount Hamilton in 2011, socializing with turkey vultures
and perching atop a Lick Observatory dome. One male bird ventured even farther, into southern Alameda County.
In 2021, a condor visited Mount Diablo. It was the first California condor to visit Contra Costa County for over a century.
In mid-2022, another condor visited the Mount Diablo region; it was seen soaring over Brushy Peak Regional Preserve near Livermore before returning to Pinnacles National Park.
The nonprofit conservation organization Save Mount Diablo has helped fund nine longrange GPS trackers to track young condors. The flight paths of the young condors are being tracked throughout the Diablo Range.
Over time, “these overlapping GPS tracks will show that the condors are increasingly flying the length of the Diablo Range, demonstrating how important it is, and that it's a significant wildlife corridor with still intact connectivity and rich biotic features,” according to the group.
“If the condor recovery continues successfully,” it said, “we can hope that a condor pair will choose to nest and raise their young on Mount Diablo. It will be historic, the first nesting pair of condors in this region in over a century.”