|Lesser Yellowlegs. San Luis Rey River mouth, Oceanside, California. September 7, 2014. Greg Gillson.|
The 1981 book by Garrett and Dunn: "Birds of Southern California: status and distribution" says that it was a fairly common fall migrant in southern California coastal estuaries. But this is no longer true. Even one bird, now, gets flagged as unusual when reported on eBird in San Diego County.
One other reason that they may be on the eBird rare bird list for the county is their common larger look-a-like relative, the Greater Yellowlegs, may be mistaken for them. If you are a bit uncertain on just how to tell Lesser Yellowlegs from Greater Yellowlegs, I wrote an identification article on this subject 4 years ago that shows an ID tip not found in most field guides.
There have been 1 to 6 birds reported most of the fall (perhaps many different birds over time?) at San Luis Rey River mouth. I saw them there at least twice. I believe I saw (and heard) one a third time, but the bird was much more distant than the one photographed above, and my photo of the other bird was not diagnostic.