I have put an updated PDF inside the California County Online Maps folder (in the member file section) for birding hotspots by county. It now has links to a map for Alameda and Contra Costa Counties which was created by Verne Nelson.
I have been unable to find online maps for many of the counties. Creating a map in Google Maps is free and quite easy to do (though it does take time). If you have location expertise and are willing to create a map to help others bird your area go for it. I would love to have links to post for all of California.
If you are aware of any missing online maps please send me the links and I'll add them to the sheet.