Peregrine Falcons of the Diablo Region
Peregrine falcons live year-round in the Mount Diablo region. Most active during the annual nesting season (February through July), these apex predators can often be spotted in Pine Canyon, where they have nested for millennia.
The nesting areas in Pine Canyon and Knobcone Point are closed to visitors from February 1st through July 31st every year to protect the birds. View Closure Notice
Photography by Wally De Young
Peregrine Team Update
As of February 1st, peregrines have been observed in both nesting sites displaying important early pair-bonding behaviors. Performing synchronized aerial acrobatics is one way the female and male begin their courtship. Photo shows peregrines in flight: female is on the left, male on the right.
Photo courtesy of Joan Duffield and Karen James
3 Falcons in cavity - Kendall Oei
Team Training Day - Dereck Love
About the Peregrines
Peregrine falcons are the fastest animals on earth and can dive at speeds over 200 mph while hunting small to medium-sized birds in mid-air. Because their survival depends on this speed, even a small injury can be deadly. Only 20% of peregrines make it through the first year of life.
On the Brink of Extinction
After World War II, extensive use of DDT devastated several bird species, peregrines among them. It interfered with calcium production, so the eggs could not withstand even the weight of an incubating parent. They cracked or collapsed, and the embryos died. As a result, by the early 1950s, peregrines had disappeared from Mount Diablo. By 1970, only two nesting pairs could be found in all of California. By 1975, peregrine numbers had dropped 80-90% in the western states and were extinct east of the Mississippi River.
DDT was finally banned in 1972. Conservation groups, businesses, biologists, and dedicated volunteers came together locally and nationally to launch recovery projects, which were successful beyond all expectations. Peregrine falcons can now be found in almost all their old haunts, including Pine Canyon, where MDIA members helped the multi-year effort to recover the species.
Today there are about 400 nesting pairs in California and 4,000 nationally, about the numbers before DDT. Two pairs live in the wilds of Mount Diablo itself, both monitored by MDIA's P-Team.
Today’s Threats to Falcons
In 1999, peregrine populations had recovered enough to be removed from the Endangered Species List. Although the threat of DDT has waned, the steep increase in visitors to our parks poses another threat to the birds. Peregrines and humans both like cliffs; however, peregrines are highly territorial during their nesting season, and if disturbed, may become too distracted to pay attention to their eggs and young. In response, Mount Diablo State Park closes the Pine Canyon cliffs and Knobcone Point area annually during the nesting season, from February 1st through July 31st. Consequently, the P-Team monitors the area intensively during this six-month season.
About the Peregrine Team
MDIA's Peregrine Team, a natural history education group, was formed in 2015 to assist park rangers during the nesting closure season. P-Team volunteers tell visitors about the peregrines, their habitat, and the importance of respecting the closure zone. P-Teamers also monitor the status of the falcons throughout the nesting season. Its members hail from a wide variety of backgrounds and include birders, hikers, runners, bikers, and equestrians, all of them nature lovers dedicated to preserving the area for future generations of people, peregrines, and the land we all depend upon.
For more information, contact Staci Hobbet, MDIA Board of Directors and Peregrine Team Lead, firstname.lastname@example.org.