Today 3/23/25, I checked the San Francisquito Creek delta from the Palo Alto Baylands boardwalk, hoping to find the Ruddy Turnstone reported there three days ago. I had no luck finding any turnstones, either from the boardwalk or from the San Francisquito Creek mouth, but did find the rock/submerged tree on which the bird was photographed (it has a distinctive finger-like projection off the top right).
The situation with the county line separating San Mateo County and Santa Clara County (SCL) is complicated in this part of the bay. A nice summary of the issues can be found on the SCVBA website: https://scvbirdalliance.org/san-francisquito-creek-mouth. As noted on that webpage, the boundary shown on the older USGS maps (1997 and before) and the Santa Clara County sccgov website are the same, but disagree with the more recent USGS maps, which shift the boundary a hundred meters or so further north and include more mudflats in SCL on the south side of the delta. (The historical USGS maps for this area can be found here: https://ngmdb.usgs.gov/topoview/viewer/#12/37.4415/-122.1426 ). https://ngmdb.usgs.gov/topoview/viewer/#12/37.4415/-122.1426
So the question is, where is the turnstone "rock" in relation to the county boundary. I was able to triangulate an approximate position today by viewing the rock from the end of the boardwalk, from the San Francisquito Creek mouth, and from a few locations in between. From the end of the boardwalk the rock was about 15 degrees to the right of the Cooley Landing Education Center (my iPhone compass works better with relative directions rather than absolutes). From the creek mouth it was about 77 degrees (East), just left of a channel marker. From all viewing locations it appeared this rock was along the edge of the channel that emanates from the outfall channel that runs along the airport and then turns northeast into the bay (this is a separate and more southerly channel than that of San Francisquito Creek). This channel can easily be seen on Google maps. With this information, I was able to get an approximate location of 37.466890, -122.107415 for the rock. This location is a hundred meters or more north of the new USGS county line and about double that north of the old USGS/sccgov county line, and thus in San Mateo County.
Do not disclose information that identifies the location of nesting birds of any species, to minimize stress on the nesting birds and the risk of vandalism or abuse.
