I wonder how many of these are misidentified as E. tenax. They look so similar. I'll watch for competition as plants come into bloom that E. tenax visits.

This is the second species for which the first sighting/posting of the year took place in Fremont and I saw a specimen a week later. The other was anise swallowtail. One was paying great attention to our parsley, and yesterday I found two eggs on the leaves. I'm a few miles north of you. I guess they spread up the Bay as the weather warms up.