In Sothern California you would expect there would very few Monarch, and you would be right. However my wife bought a small plant with small attractive red and yellow flowers about 2 years ago, you guessed it, a milkweed. Surprized to see a couple beefy colorful caterpillers devouring the plant a couple months later and some research revealed monarch catippilars. I know nothing about monarchs, except for the infamous illustration of he caterpiller on Ortho insecticide, but found them very facinating. Southern California could use some attractive widlife (its full of fuzzy brown animals) so I watched as the next year I had a brood (flock? Swarm? Platoon?) of more catipillers. This has quickly spiralled out of control as I now have five potted milkweeds, and may have to buy more (the little suckers eat more than a teenager on summer vacation). It seems there are so few milkweed that the monarch release more than a few eggs on the plants.
I finally was able to grab about five "cats" as they were running (squirmming? galloping? Girating?) off to make preperation to be a butterfly (note-to-self...buy more plants). They should hatch (explode? birth? Enter?) early November, then I guess they migrate. If you see any Monarchs with a California tan, say hi for me.