Bird has returned for its second winter at this location, and has been observed by multiple individuals this season. I don't anticipate anyone RG-ing this ob from the poor photo, but actually if you know your warblers well, the primary features eliminating other possibilities are fairly visible.
Have you seen my nuts?
We could find about a dozen Monarch larvae on a large (8-ft tall) exotic milkweed shrub, Crown Plant, Calotropis gigantea (Asclepiadaceae), near the Botanical Gardens in Balboa Park. No chrysalises were found on or near the plant.
I'm leaving the picture oriented just as the caterpillar was, foraging or getting ready to attach himself to the underside of a leaf.
Appeared to be drying its wings on the rosemary. Milkweed plants were nearby in a raised bed planter. The site is an urban community garden.
I was thinking this is Rosemary, but maybe not quite right. It was growing "wild" in the canyon.