Locals know beauty surrounds them at every turn, but what many don’t realize is their home is also a habitat unlike any in the world.
Elements present on the East County side of Mount Diablo have created the perfect recipe for nurturing raptors such as the golden eagle, a massive bird with a 7-foot wingspan.
Doug Bell, East Bay Regional Park District (EBRPD) wildlife program manager, has conducted in-depth studies on the birds of prey. He noted the district’s volunteer Golden Eagle Monitoring Team (GMT) monitors about 40 golden eagle nests, which are considered territories, in the two county areas each year.
“The northern Diablo range (Carquinez to Pacheco Pass) is thought to harbor one of the densest nesting populations of golden eagles in the world,” said Bell. “We have golden eagles thanks to healthy rangelands and habitat on both public and private lands in the area that are well managed.”
Michael Moran, EBRPD supervising naturalist at Big Break Visitor Center, explained that the abundant winds and copious ground squirrels skittering about in the open range and farmlands are factors that play into population success.
“What makes it attractive for raptors is that you figure if you’re a big bird ... your biggest use of energy is flapping wings,” said Moran. “You have those huge muscles in your chest, but when you get to a place like this, it’s windy and it suddenly reduces the need to flap – you save an awful lot of energy just that way.”
Moran said the summertime hot air rises and mixes with the cooler air coming from the ocean, which then sweeps in and blows over the top of the Mount Diablo ridgeline, creating those optimal currents for the birds to surf. In the winter, those gusts come from another direction but still make it easier to either rest or live in the area during the colder months.
“That oversimplifies it a bit, but it gives you an idea of why these birds are here,” said Moran. “We have all that open grassland and rangeland kept open by ranches and farms. There are also trees in great perches for making a nest, rocky outcrops from Mount Diablo – all meeting the needs of resident birds and migrants coming through.”
Many residents in East County have noticed the raptors in part because they’re trying to keep their otherwise flightless chickens from taking to the skies against their will. Byron resident Jackie Reckas-Retelas lives on 1.5 acres of land and recently added eight free-range chickens to her property. But one day, while flying brightly colored kites with her grandchildren, a golden eagle appeared as if from nowhere and attacked the objects.
“He flew in the middle of two kites and was tangled for a moment,” she said. “He looked like a young bird and was totally confused by his encounter with those funny-looking ‘birds’ dressed in their Sunday-go-meeting feathers.”
Reckas-Retelas said the eagle patrolled her property every day for about a week after the incident and she is currently formulating a plan to keep her chickens safe.
Moran said the encounter the Byron resident described likely was the work of a juvenile eagle.
“Some studies have shown that resident adult eagles have top priority of hunting spots, so if you get somebody who’s relatively new, you might be seeing a juvenile, looking for food and staking out their own place,” he said. “They do eat chickens. For those with free-range chickens … you may need to put thick wire over their roaming territory to protect them from avian predators.”
While the birds are protected from hunting under the Bald Eagle Protection Act of 1940, which was later amended in 1962 to include golden eagles, they are not without their share of problems in East County. Wind turbines, which provide green energy, have also been the cause for population reduction and subsequently extensive research. Some of the first wind turbines in the area were erected in the 1970s along the Altamont Pass on Highway 580. Moran said between the turbines’ placement in the wind, their tall towers (ideal for nesting) and the space cleared of grass to create a fire-defensible space (easier to spot prey), they became an unfortunate attraction to the eagles who could not see the blades when blurred with rapid movement. The newer and far more efficient wind turbines on Vasco Road move slowly, in part for their impact on these animals.
“It is important to know if we have a self-sustaining population through time in spite of wind-farm mortality,” said Bell.
Another problem for the eagles is when farmers, ranchers and homeowners attempt to tackle their ground-squirrel problem with poison.
“We recognize that people don’t want to lose their chickens or want to get rid of ground squirrels to keep their cows from breaking their ankles, but there is a way to mitigate that so the poison doesn’t go up the food chain,” Moran said.
Overall, Moran encouraged residents to get outside and take a look around.
“Go through the day proudly that you do have golden eagles in your backyard and most folks in the world will never get the chance to see something like that,” he said. “You have a chance to see some of this natural heritage that’s right outside the backdoor.”
Those with questions on reducing ground squirrel infestation without poison should contact the University of California Division of Agriculture and Natural Resources at https://ucanr.edu or 925-608-6670.