I think not "owl's clover", too. Does look like a true clover. The flower in this photo doesn't much show the prominent, feathery, awned sepal tips typical of rose clover. On the other hand, what might be construed (though blurry) as the involucre might be like the minimal one that rose clover has.

Another possibility could be Trifolium variegatum var. major or white-tip clover, which does occur in that area.

Thank you, catspa. Agree about it not being owl's clover. Looked at photos of Trifolium variegatum var. major, but I still think the photo I posted is rose clover, as it's petals seem mostly mono-colored pink, versus the multi-colored petal of Trifolium variegatum var. major, which also has very dark pink to purple color on the petal base, which my photo clearly doesn't. I'm identifying the photo strictly on the petal colors and shape, esp. since the photo is so blurry as to make it impossible to see details such as the sepals and involucre. Check out the photos at http://calphotos.berkeley.edu/cgi-bin/img_query?rel-taxon=begins+with&where-taxon=Trifolium+variegatum+var.+major and let me know if you agree my photo is more like
http://calphotos.berkeley.edu/cgi-bin/img_query?rel-taxon=begins+with&where-taxon=Trifolium+hirtum

It's true, the flower shape/color are more consistent with rose clover and perhaps the photo was taken at just the phase where the sepal tips were not so noticeable (not to mention the blurriness of the photo...). There is at least one photo like that in CalPhotos (link below), though most show those dominant feathery sepal tips.

Rose clover would also certainly be the most likely from the standpoint of commonness (does okay even in lousy years for annual clovers). Dr. Merton Love (of UC Davis, its introducer and promoter in the 1940s) advanced a non-native clover that LOVES California, for sure (and CalTrans played an additional huge role spreading it around thereafter!).

Here is a link that might be useful: T. hirtum with less noticeable sepal tips