I usually refrain from posting responses... but since this may be interesting to other Mendocino County birders (and I do not have Mr. Owings address) I am doing so. When the Peregrine Falcon was still listed as Endangered and the recovery effort was in full swing there were funds available to intensively monitor and manipulate (take eggs/place young back into) nest sites. During this time period biologist Monte Kirven was responsible for monitoring Northern California.
Based upon presentations by Mr. Kirven, and personal communication with him, we learned that Mendocino County is "very rich" in Peregrines. Based upon USFW data from about a decade ago, Mendocino County had more nesting pair of Peregrine Falcons than any other county in the forty-eight states. The county had about one-third (over twenty pair) of all the nesting peregrines in California (60+ pair). The county also get numerous migrating birds during the non-nesting season.
From my workplace at Hopland I can stand at one point and visually see four Peregrine eiries that were active all in the same year. The sites are all in almost a direct line of about twelve miles in length "as the crow flies". There is probably not another place in North America that has this high of density of Peregrine Falcon nests.
When the Peregrine Falcon was delisted and the monitoring funding ended Mr. Kirven was still concerned about the productivity of the Peregrines in county, which even though numerous, had not improved beyond a 1.4 fledglings per nest site.
To answer Mr. Owings questions...I do not know every site in the county...however I do know that Mendocino county has numerous scattered "monolith-type" basalt rocks. Almost all of these of any size with rock ledges (like Squaw Rock south of Hopland) are or have been Peregrine nest sites...so please be careful not to disturb nesting birds if you enjoy the sport of rock climbing. Most nests will fledge young by mid-June and almost always by late June. Many times birds, adult and/or young, will return to such rocky-cliff sites to roost at night also.
I hope this information is helpful. Bob Keiffer
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