Walnut Creek, CA – Since 2015, California State Parks has closed the area known as “Castle Rock” in Mount Diablo State Park to visitors annually from February 1st to July 31st to help protect the American peregrine falcon (Falco peregrinus anatum). This protected species is territorial and highly sensitive during nesting season. The rocks – located in Pine Canyon – are closed to all access during these same months each year.
The distinctive Castle Rock formations are located within Mount Diablo State Park. Visitors often access them from the East Bay Regional Park District’s Stage Road Trail, which follows Pine Creek through the Park District’s Castle Rock Regional Recreation Area and Diablo Foothills Regional Park before entering Mount Diablo State Park.
“This magnificent falcon was endangered,” said East Bay Regional Park District Wildlife Manager Doug Bell. “But thanks to the banning of DDT it has been successfully reintroduced to its historical nesting site on the rocks of Pine Canyon.”
Each year, the East Bay Regional Park District operates Diablo Foothills Regional Park and partners with California State Parks to educate rock climbers and the general public of the closure and the importance of protecting the falcon. Signs and educational panels are placed in the area to advise and educate users about the closure. Rock climbers are encouraged to utilize an alternate climbing area of the park during the closure.
“We encourage the falcons to nest here by protecting the site during the breeding season,” noted Diablo Foothills Park Supervisor Bridget Calvey of EBRPD. “Closing the area gives the falcons peace and quiet so they can produce the next generation.”
“There are plenty of other trails to explore in the area and we hope visitors use the closing as an opportunity to get to know other routes,” added Calvey.
This site was a historic nesting location for the bird, known by naturalists and scientists dating back to the late 1800s. The falcons disappeared from the area by the early 1950s due to the use of the pesticide DDT. In the 1990s, Save Mount Diablo and the East Bay Regional Park District cooperated to release captive-bred peregrines at the site; they have since resettled at the site.
The off-limits area includes all of Mount Diablo State Park’s Castle Rock area east of the Stage Road Trail and Pine Creek. The Stage Road Trail itself is not affected and will remain open. Pine Creek is the boundary between Mount Diablo State Park and the two adjacent regional parklands.
Although the peregrine is no longer endangered, it is still a fully protected species in California, and disturbance of nesting peregrines is punishable by fines and even arrest.
Public cooperation is key to the success of the program. The Park District requests that visitors abide by the posted regulations, and don’t disturb the nesting birds.
The East Bay Regional Park District is a system of beautiful public parks and trails in Alameda and Contra Costa counties east of San Francisco Bay, established in 1934. The system comprises 121,000 acres in 73 parks including over1,250 miles of trails for hiking, biking, horseback riding and nature learning.
Photo credit: US Fish & Wildlife Service
Dave Mason, Public Information Supervisor